DOI: 10.5091/plecevo.169286

Authors: Shook Ling Low

Abstract: Background and aims – While some plants achieve reproductive success through wind or deceptive pollination strategies, many animal-pollinated species depend on mutualistic interactions with pollinators, supported by floral cues, rewards, and microstructural adaptations. Despite the diversity within Araceae, pollination ecology remains poorly characterized for most species. Material and methods – To address this gap, this study investigates the flowering biology and pollination dynamics of Apoballis mutata, with particular focus on pistillate, transitional, and staminate phases of anthesis, followed by infructescence development and seed dispersal. Seeds germination trials were conducted on cotton wool in sealed Petri dishes, and fruit set was quantified from pistillate flower and berry counts. Scanning Electron Microscopy (SEM) was used to examine staminate floral structures and pollen distribution on pollinators. Key results – Three legitimate pollinators were identified, Colocasiomyia sp. 2 aff. bogneri, C. sp. 34 aff. bogneri, and C. sp. 17 aff. bogneri, along with two non-pollinating insect visitors, forming a co-occurring assemblage. Echinate pollen consistently adhered to the bodies of Colocasiomyia flies, confirming their role as effective pollinators. Unlike trapping system observed in some aroids, spathe movements in A. mutata regulated pollinator behaviour, allowing repeated visits and efficient pollen transfer. Pollinator diversity declined from the pistillate to staminate phases, with C. sp. 2 aff. bogneri remaining dominant, particularly in creamy green-spathed inflorescences. Overall fruit set exceeded 90%, with creamy melon-red spathes achieving 77.90% and creamy green spathes surpassing 100%. Conclusion – These findings reveal a specialized, non-trapping pollination system in A. mutata, enhancing understanding of its mutualistic relationship with Colocasiomyia flies and contributing new insights into the pollination ecology of Araceae.

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DOI: 10.5091/plecevo.177167

Authors: Petra De Block, Franck Rakotonasolo, Arne Mertens, Sylvain G. Razafimandimbison, Brecht Verstraete

Abstract: Background and aims – The Paleotropical tribe Vanguerieae (Rubiaceae) is centred in Africa and Madagascar. In Madagascar, many of its ca 150 species are functionally dioecious, belonging to the small genus Bullockia and two large genera, Pyrostria (~90 species) and Peponidium (~50 species). These species estimates include many undescribed species, two of which are formally described here. Material and methods – A Bayesian inference of ITS sequence data from Vanguerieae was performed to pinpoint the generic placement of the new taxa. Morphological studies were conducted based on standard methods of herbarium taxonomy. The new species are described in detail, illustrated, and compared to morphological similar species. Distribution maps are presented and the preliminary conservation status of the new taxa was evaluated using IUCN criteria. Key results – Two new species of Malagasy Vanguerieae are described. ITS data place one in the genus Peponidium and one in the genus Pyrostria. Peponidium calciphilum sp. nov. is endemic to the Tsingy of Ankarana in northern Madagascar, while Pyrostria multilocellata sp. nov. is restricted to the spiny thickets in dry southern and southwestern Madagascar. Both species occur on limestone and in dry vegetation types, have 4-merous, functionally dioecious flowers, and bilocular fruits. Peponidium calciphilum sp. nov. is characterized by ovate, sessile leaves with cordate bases, well-developed subulate stipules, glabrous shoots, ovaries, and calyces, distinct tufts of hairs at the tips of the calyx lobes, and vaulted corolla lobes with well-developed appendages. Pyrostria multilocellata sp. nov. is characterized by very small, strongly coriaceous to almost succulent leaves, single-flowered male and female inflorescences, minute flowers, and multilocellate anthers in the male flowers. Peponidium calciphilum sp. nov. is considered as Endangered, whereas Pyrostria multilocellata sp. nov. is estimated to be Near Threatened.

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DOI: 10.5091/plecevo.138752

Authors: Marco O.O. Pellegrini, David R. Hunt, Jason R. Grant, Avery Rowe, Higor Antonio-Domingues, Rafael F. de Almeida

Abstract: Background and aims – Tradescantia subg. Campelia is the most morphologically diverse and one of the most taxonomically complex subgenera of Tradescantia. This makes taxonomic efforts within this group challenging, especially due to the current lack of formal recognition of monophyletic infrageneric groups and their widespread horticultural use. Thus, continuing our previous efforts, we provide a sectional classification for the subgenus, combined with a taxonomic revision of T. sect. Rhoeo. Material and methods – This study was based on a combination of systematic, micro- and macromorphological, palynological, and horticultural data. We analysed type specimens, protologues, field images, and herbarium sheets of all names, in addition to growing all species and cultivars. We have also reviewed previously published palynological data for the recognised species and provided all needed corrections and updates, in addition to a novel interpretation of their taxonomic relevance. Key results – We propose the subdivision of T. subg. Campelia into four sections: 1) T. sect. Campelia; 2) T. sect. Corinna; 3) T. sect. Cymbispatha; and 4) T. sect. Rhoeo. These sections are supported by a combination of molecular, micro- and macromorphological, anatomical, palynological, cytological, and phytochemical data. Within T. sect. Rhoeo, we accept two species, T. spathacea and the newly recognised T. concolor. Horticulturally, we propose the T. spathacea Bantam Group, including five dwarf cultivars, while T. spathacea ‘Vittata’ is the only regular-sized variegated cultivar of wild origin. We also explore the palynology of T. sect. Rhoeo, highlighting palynotaxonomically relevant characters in Tradescantia and T. subg. Campelia. Conclusions – We lay the groundwork for ongoing and future studies on T. subg. Campelia. The recognition of sections within this subgenus will facilitate identification, communication, and enable the recognition of functional taxonomic groups for future systematic and taxonomic studies. The combination of palynology and horticulture provides further support for the taxonomy and systematics of Tradescantia, and should be consistently included in future studies of the group.

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DOI: 10.5091/plecevo.177783

Authors: Justin T. Scholten, Chelsea D. Specht

Abstract: Background and aims – Reproductive plasticity and hybridization are known to play key roles in local adaptation and range expansion in plants, yet the environmental conditions under which canonical size-dependent models of sex expression break down remain poorly understood. Arisaema serratum (Araceae), a widespread species in Japan, has long been characterized as exhibiting size-dependent sex determination, whereby individuals transition from producing staminate to pistillate inflorescences upon reaching a size threshold. Field observations from western Japan further suggest that sex expression in A. serratum may be decoupled from plant size, raising the possibility that environmental cues such as light availability override intrinsic size thresholds in some populations. Because such ecological flexibility can increase spatial and temporal overlap among sympatric congeners, we additionally evaluate whether relaxed sex determination may coincide with increased introgression within this species complex. Materials and methods – We conducted field-based demographic surveys across five populations of Arisaema on Shikoku Island, Japan, quantifying plant size, sex expression, and light intensity to evaluate environmental and morphological predictors of reproductive phase. To assess hybridization, we generated genome-wide SNP data through genotyping-by-sequencing, constructed a maximum likelihood phylogeny, and performed f-branch analyses to detect patterns of introgression among sympatric species. Key results – Our data indicate that size in fact may not be the key factor in sex determination, with light availability emerging as a stronger predictor of sex expression than size alone for populations on Shikoku Island. Preliminary genomic analyses support evidence of gene flow between A. serratum and sympatric species, indicating ongoing hybridization and introgression. Conclusions – Our findings indicate that the shift away from a strict allometric model of sex determination on Shikoku Island to a photosensitive model allowing for diphasic sexual expression likely enhances reproductive flexibility and leads to an increase in seed production in open-canopy and disturbed environments. Together, these findings provide ecological and demographic insight contributing to the broad distribution, sex determination, and morphological diversity of A. serratum.

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DOI: 10.5091/plecevo.170279

Authors: Gaik Ee Lee, S. Robbert Gradstein, Xiaolan He, Julia Bechteler, Alfons Schäfer-Verwimp, Tamás Pócs

Abstract: Background and aims – The genus Lejeunea, with about 375 accepted species, is one of the most species-rich and intricate genera of liverworts. Here, we present the first integrative, worldwide infrageneric classification of Lejeunea based on morphology and molecular-phylogenetic analyses. Material and methods – Maximum likelihood analysis and Bayesian inference of sequences from two chloroplast regions (trnL-trnF, rbcL) and the nuclear ITS region of about 35% of the species, combined with morphological evidence. Key results and conclusions – The phylogenetic analyses revealed numerous robust clades within two major lineages, corresponding to subgenera Lejeunea and Crossotolejeunea. Integrating molecular phylogenetic evidence and morphological data, we describe 15 sections: four in subg. Lejeunea (sect. Glaucescentes, sect. Lamacerinae, sect. Lejeunea, sect. Macrolejeunea) and 11 in subg. Crossotolejeunea (sect. Apolejeunea, sect. Crossotolejeunea, sect. Echinocolea, sect. Flavae, sect. Heterolejeunea, sect. Inflatolejeunea, sect. Minutilobae, sect. Nanolejeunea, sect. Papillolejeunea, sect. Sordidae, sect. Xenantholejeunea). Four sections have a neotropical distribution, three are pantropical, two are pantropical and extend into temperate regions, two are Afro-American, two are Asian, one is Asian-Australasian, and one has a tropical amphi-Pacific range.

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DOI: 10.5091/plecevo.172526

Authors: Murielle Simo-Droissart, Olivier Lachenaud, Moses Libalah, Bonaventure Sonké

Abstract: Background and aims – Riverine habitats along the Sanaga River in Cameroon were until recently little-explored by botanists, although they are facing increasing threats, notably from the construction of hydroelectric dams. Recent botanical inventories in the area have led to the discovery of several taxonomical novelties, including a new species of Phragmanthera (Loranthaceae) that is described here. Material and methods – This paper is based on field studies and examination of herbarium collections of the new species and its relatives. Classic practices of herbarium taxonomy have been applied. The conservation status of the new species is assessed following the IUCN Red List Categories and Criteria. Key results – Phragmanthera bidaultii sp. nov. is identified by its non-septate anthers (a unique character in the genus), by the patent to reflexed corolla lobes with the apex thickened into a conical appendage, and by its relatively narrow leaves, initially with sparse rufous barbellate hairs but soon becoming glabrescent on both sides. It has a very restricted distribution along the Sanaga River in Cameroon, where it grows in riparian forest, and it is assessed as Endangered (EN).

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DOI: 10.5091/plecevo.165607

Authors: Gabriela Cruz-Lustre, João A.N. Batista

Abstract: Background and aims – Habenaria is the largest genus of predominantly terrestrial orchids and the genus with the largest number of species in the family in Brazil. Field expeditions to Grão Mogol, in the northern part of the Espinhaço range of Minas Gerais, Brazil, led to the discovery of a taxon within the Habenaria nuda complex that could not be assigned to any of the known species within the complex. This study aimed to investigate the identity and taxonomic status of this taxon. Material and methods – We analysed the morphology of the taxon and compared it with herbarium specimens of morphologically similar species. We assessed its phylogenetic relationships using parsimony, maximum likelihood, and Bayesian inference, based on nuclear (ITS and ETS) and plastid (matK-trnK and rps16-trnK) DNA sequences. Key results – This taxon belongs to a large clade that mostly comprises species from the Cerrado domain. It differs from other species in the Habenaria nuda complex in that it has patent lateral sepals, and petal anterior segment and lip lateral segments that are shorter than the petal posterior segment and lip median segment, respectively. It also has small auricles located below the rostellum arms and anther canals. Based on these results, we described it here as a new species, Habenaria adamantina sp. nov. We present a distribution map, alongside comments on the taxon’s habitat, phenology, and preliminary conservation status, as well as an identification key to differentiate it from other species within the complex. The number of Habenaria species in Grão Mogol has increased from four to 12 species, with the new species being the only one restricted to the region. Conclusion – This study highlights the importance of both continuous and group-specific botanical surveys for documenting biodiversity, particularly for species that are seasonal, inconspicuous, or present in low numbers.

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DOI: 10.5091/plecevo.172513

Authors: Luiz Henrique M. Fonseca, Ricardo da Silva Ribeiro

Abstract: Background and aims – During ongoing morphological studies of Adenocalymma, we realized that nomenclatural updates are necessary in the genus. Here, we propose a new circumscription of A. acutissimum and the description of the new species A. darwinii. Material and methods – Morphological and phylogenetic evidence support the new circumscription of A. acutissimum, while the new species is recognized based on morphological grounds and compared to A hirtum and A. salmoneum. Key results – We removed the taxa A. comosum, A. comosum var. lanceolatum, and A. nitidum as synonyms of A. acutissimum. We also presented a detailed description for A. darwinii sp. nov., an illustration, and information on its distribution, habitat, phenology, and extinction risk. A map showing the occurrence of both A. comosum and A. darwinii sp. nov. is shown. Conclusion – These results emphasize once again the importance of taxonomic studies in the Brazilian Atlantic Forest and highlight conservation concerns for its flora.

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DOI: 10.5091/plecevo.152818

Authors: Carolyn Elinore Barnes Proença, Jair Eustáquio Quintino de Faria, Marla Ibrahim Uehbe de Oliveira, Julia Sonsin-Oliveira, Gustavo Hiroaki Shimizu, Vanessa Graziele Staggemeier

Abstract: Background and aims – Myrcianthes is a New World genus of Myrtaceae with 36 species, diverse in the Andes, and often dominant in montane forests. It is found from the Pacific to the Atlantic, from sea level to 3729 m, and its total latitudinal range is almost 62°. Its old age, combined with a wide ecological and geographic range, and the many narrow-endemic species, make it of phytogeographic and evolutionary interest. Material and methods – Altitudinal, geographic, and wood anatomy data of the genus were compiled from literature and online herbaria and curated to eliminate errors and produce a reliable dataset. ML and Bayesian phylogenetic trees based on ITS, ETS, matK, and psbA-trnH of 11 Myrcianthes species, in a matrix of 123 species, were constructed. The Bayesian tree was calibrated with three macrofossils and three secondary calibration points and used to infer biogeographic history and to estimate ancestral ranges using BioGeoBEARS. Key results – Myrcianthes has the widest combined altitudinal/latitudinal range in Myrtaceae. Narrow-endemic species are concentrated either in the high-latitude lowlands or the low-latitude highlands. Myrcianthes diverged from Eugenia in the early Oligocene but did not diversify before the mid-Miocene (later than Eugenia). Myrcianthes diversified from the south into South America, Central America, and the Caribbean. Its ancestral range emerged as the Chacoan/Paraná dominions, consistent with the extinct temperate/subtropical austral forest. After splitting from M. coquimbensis, endemic to Chile, the main clade divided into a lowland clade (most diverse in eastern South America) and a highland clade (most diverse in the Andes). The clades are sympatric near the inferred root of the tree and probably meet again in Colombia and Venezuela. Myrcianthes wood anatomy appears to differ from that of Eugenia by the occurrence of helical thickenings in the vessels and absence of prismatic crystals in the axial parenchyma, but sampling is still incomplete.

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DOI: 10.5091/plecevo.160648

Authors: Diego Villar-Morales, Alejandra Moreno-Letelier, Marcelo Rodrigo Pace, Miguel Ángel Pérez-Farrera

Abstract: Background and aims – Chamaedorea is the largest genus of neotropical palms distributed mainly in lowland rainforests and montane cloud forests from Mexico to Bolivia. Species delimitation in this genus remains problematic due to high morphological variation and inconsistent taxonomic treatment of such variation. Chamaedorea elatior, a climbing species from southern Mexico and northern Central America, exemplifies these challenges with several historical synonyms and informally recognized morphotypes. This study evaluates the morphological variation in vegetative characters between this species’ most characteristic two morphotypes, cespitose and solitary, to evaluate their taxonomic distinctiveness. Material and methods – Six populations of C. elatior were sampled in Mexico and Guatemala, representing both solitary and cespitose morphotypes. Thirteen morphological leaf characters were measured from mature individuals. Data were examined using univariate and multivariate analyses (NMDS, k-means clustering, PCA, MANOVA, LDA) to evaluate morphological variation between the morphotypes and populations. Discriminant analyses were also used to assess classification into either morphotype. Key results – Univariate analyses revealed significant differences between morphotypes in most measured characters, mainly those associated with leaf size. Similarity analyses recovered both morphotypes as being distinct from each other. PCA showed notable separation of the morphotypes along the first component that summarized leaf and median leaflet size. Both MANOVA and LDA confirmed significant differences between morphotypes and resulted in high accuracy classification. Conclusion – Leaf morphology clearly distinguishes the solitary and cespitose morphotypes of C. elatior, supporting their potential delimitation as separate species. The branching habit of the cespitose form further reinforces this distinction. While current results support species-level recognition, additional evidence from reproductive characters, niche, and genetic divergence is recommended to confirm a possible species delimitation.

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DOI: 10.5091/plecevo.157554

Authors: Marco M. Jiménez, Luis Baquero, Henry X. Garzón-Suárez, Carlos Martel, James A. Chamaya G., Nadia Lapo-González, Florian A. Werner, Gabriel A. Iturralde

Abstract: Background and aims – Telipogon is an orchid genus with a main diversity centre located in the tropical Andes. Some small-flowered Telipogon species, formerly classified under Stellilabium, remain poorly known. During recent fieldwork in southern Ecuador, an undetermined species of a miniature Telipogon was recorded and collected. We aimed to taxonomically identify the orchid and understand its phylogenetic relationships. Material and methods – We conducted field work in diverse parts of Ecuador and Peru, revised material deposited at various herbaria, and records available on iNaturalist. Furthermore, we extracted, amplified, and sequenced DNA sequences to evaluate the phylogenetic position of the undetermined species. Key results – The unidentified species turned out to be an undescribed Telipogon species, which we describe and name here as T. villonacoensis. It has also been recorded in Colombia and Peru, an unusually wide distribution for a Telipogon species. Telipogon villonacoensis is distinguished by its pale green to yellow flowers, the elliptic petals and lip, minute lobes and red coloration at its basal third. This species appears to have a patchy distribution and specialized habitat preferences, growing as an epiphyte in montane shrublands and forests. Although fewer than 200 individuals have been documented so far, and its habitats face ongoing threats, our conservation assessment indicates the species could be classified as not threatened. Phylogenetic analyses resulted in a well-resolved tree, in which T. villonacoensis is placed within the clade of the South American miniature Telipogon and sister to, but genetically distinct from, T. pogonostalix, though it is morphologically more similar to T. alexii, a species placed in another subclade of South American miniature Telipogon. Conclusion – Our results highlight the underestimated diversity and distribution range of miniature Telipogon and underscore the need for continued collaborative exploration and conservation in Andean ecosystems. These findings will contribute to a better understanding of orchid diversity and evolution of Telipogon species.

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DOI: 10.5091/plecevo.152748

Authors: Eileen J. Cox

Abstract: Background and aims – Over 40 years ago, I explored the use of symmetry and structure as taxonomic criteria for naviculoid diatoms, arguing that structure was the more informative character. This paper examines subsequent progress in the understanding and systematics of naviculoid diatoms with particular reference to the treatment of symmetry as a taxonomic criterion. Methods and key results – The diatom literature since 1979 has been reviewed showing how SEM studies and data on wall morphogenesis have improved our knowledge of diatom wall structure and ontogenetic pathways. Understanding the inherent asymmetry in raphid diatom valves led to the recognition of two types of dorsiventrality within the Cymbellales and underpins the separation of cymbelloid taxa in different families. Hypotheses of character homology in the Naviculaceae have been supported by more recent molecular phylogenetic analyses, also revealing how shape and symmetry can vary within this family. Over-emphasising the significance of a particular character (out of familiarity or a priori preference?) can lead to relevant discriminative characteristics being ignored. The validity of some new genera is questioned and generic descriptions should be revised. Conclusion – Whereas valve shape and symmetry remain useful features when identifying taxa, systematic relationships are revealed through wall structure and should be the basis for diatom systematics. Nevertheless, it is important to discriminate between homologous and homoplasious characters and to apply terminology accurately.

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DOI: 10.5091/plecevo.146274

Authors: Piero G. Delprete, Jomar G. Jardim

Abstract: Background and aims – Single-stemmed plants 20–100 cm tall, with sessile or subsessile leaves in terminal rosettes gathering leaf litter, and axillary, 1–3-flowered inflorescence, from the state of Rio de Janeiro, southern Brazil, and from French Guiana, have traditionally been identified as Faramea tinguana. The disjunction of more than 3,200 km air distance between French Guiana and Rio de Janeiro stimulated an in-depth analysis of the specimens from those regions to evaluate if any morphological character might distinguish them. Material and methods – This study is based on examinations of herbarium specimens, material preserved in 60% ethanol, and field observations. Herbarium specimens were studied either on site or through loans from the CAY, CEPEC, G, G-DC, K, L, MO, NY, P, RB, U herbaria. Digital images of herbarium specimens were analysed through virtual herbaria. Traditional practices of herbarium taxonomy have been applied. A preliminary conservation status assessment of each species studied was made using the IUCN Red List Categories and Criteria. Results – The names F. tinguana and F. megalophylla are here lectotypified, and are treated as synonymous. Numerous reproductive characters support a clear distinction between the specimens from Rio de Janeiro and those from French Guiana traditionally identified as F. tinguana. Hence, the two distant populations are here treated as two distinct species. Faramea humicapiens, endemic to French Guiana, is newly described, and F. tinguana is restricted to the state of Rio de Janeiro. Faramea humicapiens is evaluated as Vulnerable and F. tinguana as Critically Endangered. A discussion on Neotropical litter-gathering Rubiaceae is also presented.

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DOI: 10.5091/plecevo.140133

Authors: Mayte Stefany Jiménez-Noriega, Alejandro De la Rosa-Tilapa, Alejandro Torres-Montúfar

Abstract: Background and aims – Calcium oxalate crystals are the most common biominerals in plants and have a wide variety of forms, such as styloids, druses, raphides, prisms, and crystal sand. The shape, position, and number of crystals in plant tissues can have taxonomic value. For Rubiaceae, one of the most diverse angiosperm families, the presence of crystals may be taxonomically informative. In Mexico, one of the most diverse Rubiaceae genera is Randia, which occurs in arid, tropical, temperate, and coastal dune vegetation. The aim of this study is to explore the taxonomic value of calcium oxalate crystals in Randia. Furthermore, we aim to ascertain whether these crystals respond to the environmental conditions in which the plant grows. Material and methods – Ten Mexican Randia species were selected, three of which included individuals from different vegetation types. For each individual, three mature leaves obtained from herbarium samples from MEXU and FESC were selected for SEM processing and leaf clearing. Key results – Druses in the spongy parenchyma and palisade parenchyma were constant in all the species studied. The druses in the palisade parenchyma were always larger than those in the spongy parenchyma. In addition to druses in the intracellular parenchyma, R. tomatillo presented extracellular prisms in the epidermis as well as extracellular prisms and aggregate prisms in the mesophyll, which is a rare characteristic in Rubiaceae. Conclusion – The constant presence of druses in the mesophyll could serve as a possible characteristic to diagnose the genus Randia, whereas the variable presence of druse crystals in the epidermis and veins could be related to environmental factors. The prisms in R. tomatillo may be related to its occurrence in the harsh environment of coastal dunes.

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DOI: 10.5091/plecevo.145707

Authors: María Guadalupe Maldonado-Borja, Rosa Cerros-Tlatilpa

Abstract: Background and aims – Struthanthus is a neotropical genus with 60 to 70 species, distributed from northern Mexico to Argentina. Eighteen species are reported in Mexico. During fieldwork to investigate Struthanthus in Mexico, a new species was collected in the state of Guerrero. We present a full description, distribution map, illustrations, and photographs of an unusual new Struthanthus species endemic to Guerrero, Mexico. Material and methods – This study is based on fieldwork, literature revision, and examination of herbarium material. Collected specimens were prepared for storage in the herbarium, analysed, measured, described, and photographed. Preliminary conservation assessment is based on spatial analyses following IUCN guidelines and criteria. Key results – We propose a new species of Struthanthus for Guerrero, Mexico, S. longipetiolatus. This species is only known from cloud forests, oak-pine forests, and oak forests in the province of Sierra Madre del Sur, in the state of Guerrero. A distribution map and an identification key are provided for S. longipetiolatus and its morphologically similar congeners in the region. Conclusion – The newly described species increases the number of Struthanthus species in Mexico to 19 and the number of endemic species to nine. This discovery underlines the need for continued botanical inventories and research on parasitic plants.

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DOI: 10.5091/plecevo.140649

Authors: Rosana Romero, Luciano Pataro, Ana Flavia A. Versiane

Abstract: Background and aims – The genus Microlicia consists of 286 taxa, 82 of which are found in Bahia, Brazil. This genus features pentamerous flowers, occasionally hexamerous to decamerous; a hypanthium with or without bristles, isomorphic to dimorphic androecium; tetrasporangiate or polysporangiate anthers; and pedoconnective prolonged below the theca with a ventral appendage. The ovary has a glabrous apex, and the fruit is capsular with either basipetal or acropetal dehiscence and a columella that can be persistent or deciduous. In this study, we describe three new species of Microlicia found in Bahia, Brazil, and provide a checklist of Microlicia species with yellow corollas. Material and methods – The morphological descriptions are based on examinations of the Microlicia collections housed in six herbaria. Along with the descriptions, we provide comparisons with morphologically similar species, a distribution map, conservation status assessments, and illustrations. Key results – We describe Microlicia aequalis, Microlicia eimeariana from Catolés, and Microlicia xanthopetala from Mucugê, Bahia, Brazil. We have preliminarily assigned these three species as Data Deficient (DD) according to IUCN Red List criteria.

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DOI: 10.5091/plecevo.128682

Authors: Alexander Ordynets, Gérald Gruhn

Abstract: Background and aims – During fieldwork in French Guiana in 2018, two fungal specimens resembling Subulicystidium oberwinkleri were collected. This study aims to clarify species- and genus-level assignment of this material and of S. oberwinkleri. Material and methods – Corticioid fruiting bodies were examined under a light microscope, and spores from the spore prints were studied morphometrically. DNA sequences of large subunit-coding DNA and internal transcribed spacer were used for maximum likelihood and Bayesian phylogenetic analyses. Furthermore, guanine-cytosine content was calculated for the LSU dataset, and UNITE Species Hypotheses Matching Analysis was performed for newly generated ITS sequences. Key results – The new genus, Palliocystidium, is introduced in the family Hydnodontaceae, based on the peculiar pattern of cystidial encrustation (crystalline plates of various shapes) and cystidial septation and supported by results of phylogenetic analyses. Within the new genus, the new species P. chlamydatum from French Guiana is described. In addition, Subulicystidium oberwinkleri is transferred to Palliocystidium. The two species can be distinguished by the size of their reniform spores. Both species display high levels of guanine-cytosine content at the scale of the order Trechisporales. Conclusions – In the newly introduced genus Palliocystidium and genera Subulicystidium and Luellia, there is significant potential for further exploration of species diversity and generic boundaries. Additional intensified fruiting-body-based sampling of taxa and genes is necessary to clarify the relationship of genera within Hydnodontaceae.

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DOI: 10.5091/plecevo.140559

Authors: Kamila Grzebielucka, Felipe Micali Nuvoloni, Rosângela Capuano Tardivo

Abstract: Background and aims – This study investigates the phenotypic plasticity of Wittrockia cyathiformis (Bromeliaceae), an endemic species of the Atlantic Rainforest, with the aim of evaluating its morphological variation in relation to different life forms and forest types, specifically Dense Ombrophilous Forest and Mixed Ombrophilous Forest. Material and methods – Field collections were conducted in State Conservation Units and Campos Gerais National Park in Paraná during 2022 and 2023. We measured vegetative morphometric parameters of six to eight bromeliads for each life form (epiphytic, saxicolous, and terrestrial) in each forest type, totalling 43 specimens, with 22 from Dense Ombrophilous Forest and 21 from Mixed Ombrophilous Forest. Additionally, we assessed the national conservation status of the species in Brazil. Key results – The different forest types of the Atlantic Forest exert a greater influence on the phenotypic variation of W. cyathiformis than life forms, with only leaf sheath length being greater in epiphytes and smaller in terrestrials. On the other hand, significant variations in leaf morphometry, such as leaf width and spine size, were strongly associated with the bioclimatic conditions of each forest type. Specimens from Dense Ombrophilous Forest exhibit characteristics typical of species adapted to warm and humid environments, with broader leaves, whereas those from Mixed Ombrophilous Forest have narrower leaves and smaller spines. Conclusion – The different life forms of this species do not result in significant morphometric changes. However, its phenotypic plasticity is strongly influenced by the different forest types, which may favour adaptation to variable environmental conditions. Despite this adaptive capacity, W. cyathiformis is classified as endangered (EN) in its area of occupancy in Brazil. The ongoing habitat loss highlights the need for conservation measures to ensure the long-term persistence of its populations.

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DOI: 10.5091/plecevo.140657

Authors: Bruno Francisco Sant’Anna-Santos, Elaine Lopes Pereira Nunes, Rafael Micheli, Dayana Maria Teodoro Francino

Abstract: Background and aims – The Serra do Ambrósio is a mountain with a unique vegetation called carrasco. The carrasco is characterised by sandy soils of high granulometry and is home to rare species. During the current research on the Arecaceae flora of the Diamantina Plateau, a new Syagrus species was discovered, which is described here. Material and methods – The morphology and anatomy are described based on field collections. The pinnae anatomy was analysed using LM (free-hand cross sections). The new species belongs to the Syagrus glaucescens complex, and an identification key and a distribution map were created. Key results – Syagrus harenae resembles S. glaucescens, but some characteristics easily differentiate it, such as the small size, lax pinnae, symmetric pinnae tips, ramenta scales, a scattered thin indumentum on the peduncle, inflorescences and fruits orangish-yellow, and pistil with indumentum. The new species also possesses flowers arranged in tetrads and pentads and is the first species of Syagrus showing two sepals, petals with imbricate tips, staminodes with anthers, and frequently lacks staminodial rings. The pinnae anatomy of the new species also resembles S. glaucescens, which indicates their relatedness. However, reliable differences in pinnae anatomy set the new species apart, such as the fibrous ring reaching the abaxial hypodermis and the large first adaxial fibre bundle near the margin. The new species is assessed as critically endangered. Conclusion – Syagrus harenae is the first endemic species of the genus described for the Serra do Ambrósio and possesses striking characteristics, such as the re-greening of the pistillate flowers and flowers arranged in tetrads and pentads. The type population corroborates the Diamantina Plateau and its disjunctions as one of the centres of diversity for Syagrus. The discovery of this new species reinforces the uniqueness of the local flora and its classification as a priority area for conservation.

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DOI: 10.5091/plecevo.127131

Authors: Attila Mesterházy, Marc Reynders, Mylor Ngoy Shutcha

Abstract: Background – During field work performed in 2018 by the University of Lubumbashi in the Katanga region of D.R. Congo, a peculiar Cyperus species was discovered at the edges of a thermal spring in the southwest corner of the Upemba graben, near the city of Luena. Material and methods – Herbarium material from the collected plant was studied and used as a basis for illustrations and a SEM study of the nutlets. A preliminary IUCN Red List assessment was performed according to the IUCN Guidelines and Criteria. Results – Cyperus kilelai, a new species from Katanga in D.R. Congo, is described and illustrated. This small tussocky species is characterised by weakly 3–4 angled dimerous nutlets with stigma branches in ad- and abaxial positions and glumes of 2.5–3.2 mm long. It is currently only known from its type location. Thermal springs in this region are of interest for the development of geothermal power plants in the near future. Based on the restricted area, a small population size, and a plausible future threat, the conservation status of this species is preliminarily assessed as Vulnerable.

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DOI: 10.5091/plecevo.124295

Authors: Petra Wester, Patricia Brühn

Abstract: Background and aims – Fluorescence is the emission of light by a fluorophore that has absorbed light of shorter wavelengths. While the role of fluorescence in visual communication has been documented in some animals (budgerigars, gelatinous zooplankton), it is controversially discussed in plants. Floral nectar fluorescence has been mainly found in flowers pollinated by bees. It has been suggested as direct visual cue by which bees can evaluate the available quantity of nectar, thus being important for pollination and foraging efficiency. However, this function has been questioned, since fluorescence is said to be obscured by floral reflections due to low quantum efficiency. The aim of this study was to examine the nectar of plants pollinated by non-flying mammals, namely Eucomis regia, Massonia grandiflora, M. echinata, and M. pustulata (Asparagaceae) from South Africa. Material and methods – To detect possible fluorescence in flowers, the plants were illuminated in a darkened room under UV light and photographed with a camera equipped with a UV/IR cut filter (transmitting at 400–700 nm). Key results – Within the inflorescences, the nectar of all species showed blue to bluish fluorescence and UV absorption. Separated nectar also fluoresced. Conclusion – As fluorescence in flowers occurs not only in bee-pollinated plants but also in plants pollinated by wind, and by nocturnal or crepuscular pollinators (non-flying mammals, bats, moths) for which floral scent is an important attractant, floral fluorescence seems to have no adaptive value for the attraction of flower visitors. We discuss the potential role of fluorescence in flowers as just a by-product of compounds that might have other functions such as visual attraction by reflection (or UV absorbance), protection of genetic material in pollen from UV induced damage, or as a floral filter causing nectar to be bitter, repelling ineffective pollinators but not effective ones.

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DOI: 10.5091/plecevo.121829

Authors: David M. Williams, Tsvetoslav Georgiev, Tanja M. Schuster, Carlos E. Wetzel

Abstract: Background and aims – Euodia frauenfeldii has the characteristic ‘semi-circular’ or ‘crescent-shaped’ valves found in most species of Euodia, but as it also has a pair of conspicuous transapical costae, it was later transferred to Eunotogramma. Examination of the structure of its valves and girdle has led to a reassessment of its taxonomic position. Material and methods – We discuss various aspects of terminology used for the parts of the valve, their abbreviations used throughout the literature and provide a detailed taxonomic background to both Euodia and Eunotogramma. Key results – A new genus, Moralesonia is described and its relationships discussed.

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DOI: 10.5091/plecevo.112250

Authors: Gerardo Manzanarez-Villasana, María C. Mandujano

Abstract: Background and aims – Opuntia s.s. (Cactaceae) is one of the most diverse genera in the subfamily Opuntioideae, with approximately 220 species. The considerable morphological and anatomical diversity among these species has resulted in a remarkable adaptative plasticity, evident in both intra- and interspecific variability. Our study system is Opuntia streptacantha, which has two flower colour morphs: yellow and orange. The objective is to determine if there are morphological differences in the reproductive and vegetative structures between floral morphs. Material and methods – We measured 8 cladode traits (n = 20 cladodes for each floral morph) and 17 flower traits (n = 30 flowers per morph), and reproductive phenology was recorded for both morphs to describe their phenophases (n = 10 individuals per morph). Key results and conclusion – We found that floral colour morphs of O. streptacantha showed significant differences mostly associated with flower traits. Principal component analysis revealed seven components that explained 80% of the total variation, namely total flower length, number of stamens, distance between anther and stigma, number of pollen grains, style length, equatorial diameter of the ovarian chamber, pericarp width, and number of areole lines. Some individuals of O. tomentosa were classified as floral morphs of O. streptacantha, not having a clear separation between the species. The phenology of the floral colour morphs showed a slight lag in their peak flowering and fruiting. Very high flowering synchrony was found for each floral morph and between them. The modifications found in the flowers of O. streptacantha may be associated with a possible hybridization with O. tomentosa favouring the appearance of the two floral morphs.

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DOI: 10.5091/plecevo.121915

Authors: Emerson R. Pansarin, Marcelo R. Miranda

Abstract: Background and aims – Brazil has more than 40 species of Vanilla. Some taxa have been considered to be obscure since they are known only from the type specimen. This is the case of some south-eastern Brazilian species such as V. dubia and V. dungsii. While studying the diversity of Brazilian Vanilla, plants of an unidentified species were found in Ubatuba, São Paulo, Brazil. After flowering, it was confirmed that the species corresponded to the obscure V. dubia. Material and methods – A redescription of V. dubia is provided and a morphological comparison with the related taxa V. dungsii and V. paulista is presented. An illustration of V. dubia is provided, and its geographic distribution is presented. The identity of the enigmatic V. dungsii is also clarified based on holotype examination and on images of living specimens. Key results – Vanilla dubia is recognized by its coriaceous leaves with prominent vascular bundles in transverse section, by its white 3-lobed labellum with yellow lobes and undulate-crenulate margins, and by its tuberculate appendages on the apical portion of the labellar crest. Morphological characteristics suggest a close relationship of V. dubia with V. dungsii and V. paulista. Vanilla dubia occurs in the Dense Ombrophilous Forest, while V. paulista occurs in the Semi-deciduous Mesophytic Forest, and V. dungsii is endemic to the Dense Montane Ombrophilous Forest. Based on current data, V. dubia is assessed as Endangered. Conclusion – Evaluation of vegetative and reproductive characters from living and herbaria specimens is crucial to understanding the identity and species boundaries of Vanilla. The data presented here show that the species occurring in the Atlantic Forest, V. dubia and V. dungsii, are more closely related to each other than to V. paulista, which occurs in Semi-deciduous Mesophytic Forests. A proposal to change the status of V. dungsii as a subspecies of V. dubia can be further considered.

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DOI: 10.5091/plecevo.119907

Authors: Bart Van de Vijver, Wolf-Henning Kusber, Ingrid Jüttner, Tanja M. Schuster, David M. Williams

Abstract: Background and aims – Small-celled araphid diatoms form an important part of the diatom flora in our rivers and lakes. Although several of these species are frequently reported, their correct taxonomic identity is often obscured due to a lack of good knowledge of the original (type) material. Material and methods – Several historical (nineteenth century) original samples were retrieved from different European and North American diatom collections. The samples have been analysed using light (LM) and scanning electron microscopy (SEM). Key results – Staurosirella crux comb. nov., based on Ehrenberg’s Navicula crux, proved to be the oldest valid name for Staurosirella harrisonii, the latter now being considered a younger synonym. A new European species, S. neorhomboides sp. nov., is described to replace the name S. rhomboides, now considered a younger synonym of S. leptostauron. The North American populations of S. rhomboides and S. martyi differ sufficiently from the type populations and are described as new species: S. moralesii sp. nov. and S. manoyloviana sp. nov. The new combination Staurosirella informis comb. nov. is proposed for a taxon described in 1856 from the French Pyrenees as Odontidium informe. Staurosirella leptostauron turns out to be insufficiently described and is now documented for further use. Conclusion – The analysis of the original (type) material corrected several taxonomic errors and better characterised the morphology of several commonly observed Staurosirella species.

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DOI: 10.5091/plecevo.116102

Authors: Christine Cocquyt, Jonathan C. Taylor

Abstract: Background and aims – Actinella species from Central Africa are only rarely reported. The acid waters from many stream and small rivers in the Congo Basin form a potential environment for species of this genus. We studied several samples from the region of Yangambi to confirm whether species belonging to this genus are present. Material and methods – Samples for diatom investigation were collected in several streams and small rivers (Moni, Ngima, and Libongo), in the tropical rainforest in the Yangambi Biosphere Reserve, Tshopo Province, Democratic Republic of the Congo. The samples were prepared to obtain permanent microscope slides for light microscopy studies using standard methods and cleaned material for scanning electron microscopy. Key results – A novel Actinella was observed in the studied samples. The taxon was compared to other species such as A. disjuncta, A. lange-bertalotii, A. modesta, A. pereunotioides, and A. pseudohantzschia, although the new species morphologically resembles most A. eunotioides, a species discovered in the Amazon basin in Brazil, and A. eunotioides var. minor, described in 1966 from the Central African Republic. The taxon observed in our material differs from A. eunotioides mainly in the valve dimensions, being much smaller, and the higher density of the marginal spines. Stria density also tends to be coarser. The valve length of A. eunotioides var. minor, on the other hand, corresponds with the smallest valves of our taxon but the valves are narrower, with a higher stria density. The ventral margin is slightly convex, while in the new taxon it is slightly concave. Moreover, in the original description of A. eunotioides var. minor, the absence of spines is mentioned, while they are present on the valves in the materials we investigated. Based on the observed morphological differences, we consider the taxon recorded in the streams and small rivers in the Yangambi Biosphere Reserve distinct from A. eunotioides and its var. minor and subsequently, we describe Actinella kufferathiana as a species new to science.

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DOI: 10.5091/plecevo.115801

Authors: Natalia Kochman-Kędziora, Bart Van de Vijver

Abstract: Background and aims – The genus Orthoseira is generally known to be typically aerophilous. Despite the worldwide occurrence of the genus, most of the Orthoseira species seem to have a rather restricted biogeographic distribution, often being part of an endemic diatom flora. During a survey of the aerophilic diatom flora in Papua New Guinea (Karkar Island, Boisa Island), four morphologically distinct Orthoseira taxa have been observed. Material and methods – The morphology of four Orthoseira species was investigated in detail using light microscopy (LM) and scanning electron microscopy (SEM). Key results – The morphology of all four species is discussed and compared to known species worldwide. The main differences between the species include: the presence and shape of linking structures, the number of rows of perforations on the copulae, presence/absence of internal caverns and the external structure of the carinoportulae. Two species, with a unique set of features, are described as new to science: Orthoseira iserentantii sp. nov. and Orthoseira papuensis sp. nov. Conclusions – The observation of four Orthoseira species, including two species new to science, confirms that the diversity of the genus Orthoseira is underestimated.

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DOI: 10.5091/plecevo.116544

Authors: Abraham E. van Wyk, Richard G.C. Boon

Abstract: Background and aims – The species name Gymnosporia filiformis, validly published in a 1927 revision of South African Celastraceae, was based on syntypes representing both Maytenus cordata and a new species. Subsequent studies supported the distinction of Gymnosporia and Maytenus as separate genera. From 1984, this new species was provisionally referred to by the designation “Maytenus sp. A”. Maytenus in Africa comprises a diverse group of species not closely related to the New World members of Maytenus. Here, we clarify the taxonomic identity and generic placement of G. filiformis, and compare it with species with which it has historically been confused. Material and methods – Descriptions and observations are based on extensive field work, supported by conventional taxonomic methods, including study of relevant literature and herbarium collections. Key results – The name Gymnosporia filiformis is lectotypified using a syntype representing “Maytenus sp. A”. We describe a new monotypic genus, Marijordaania, to accommodate “Maytenus sp. A”, and propose the new combination, Marijordaania filiformis. An amended description is provided for the species. It is morphologically quite different from Maytenus cordata, but also from Maytenus acuminata and Maytenus abbottii, species with which it has been confused in the past. Marijordaania filiformis grows in the understorey of evergreen Scarp Forest and is relatively rare, known with certainty only from KwaZulu-Natal and the Eastern Cape provinces, South Africa. A preliminary conservation assessment suggests that M. filiformis should be classified as Endangered. Conclusion – Marijordaania filiformis is a taxonomically isolated species with no apparent close relatives among African Celastraceae. While the generic status of other African members of Maytenus still needs to be resolved, it would not impact the taxonomic status of Marijordaania. In a recent key for Celastraceae genera based on morphology and geography, M. filiformis ran to the genus Euonymus, but this association lacks support from available molecular evidence.

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DOI: 10.5091/plecevo.110654

Authors: Bruno Francisco Sant`Anna-Santos

Abstract: Background and aims – The highlands of the Chapada dos Veadeiros region comprise one of the largest savannah areas in central Brazil. The region includes large areas of the rare and little-known cerrado rupestre, which is home to numerous endemic species. During research on the Arecaceae flora of Chapada dos Veadeiros, a new species of Butia was discovered, and it is described here. Material and methods – The morphology and anatomy are described based on field collections. Following the default methodology, pinnae and flowers were analysed using LM (freehand cross- and longitudinal sections) and SEM. The new species is compared to its morphologically similar species from the Brazilian central plateau, and an identification key and distribution map were established. Key results – At first sight, the new species Butia soffiae resembles B. archeri, but with staminate and pistillate flowers, which are always purple, different in size, and congested in the rachillae. After close inspection, it is morphologically allied to B. buenopolensis, differing mainly by its glaucous peduncular bract – similar size to the inflorescence, herbaceous peduncle, numerous rachillae, purple floral colour, and inconspicuous staminodes. Differences in leaf anatomy, such as the presence of raphides, a cross-sectionally truncated midrib, and the number of accessory bundles on the midrib, also support the description of a new species. Two structures were recorded for the first time for the genus: squamiform trichomes at the base of the pistil and osmophores on the staminodes. The new species is assessed as Critically Endangered based on the restricted area of occurrence and anthropogenic threats. Conclusion – Butia soffiae is the first endemic Butia species described in Chapada dos Veadeiros. The type population is located near Chapada dos Veadeiros National Park, which is the subject of a bill that aims to reduce its area by 73%. The discovery of this new species reinforces the uniqueness of the local flora and the importance of maintaining the park.

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DOI: 10.5091/plecevo.101657

Authors: Rafael F. de Almeida, Isa L. de Morais, Marco O.O. Pellegrini, Cassio van den Berg

Abstract: Background and aims – Cordobia, Gallardoa, Mionandra, and Peixotoa (Stigmaphylloid clade, Malpighiaceae) are four small, closely related genera comprising shrubs or lianas endemic to South American savannas, dry forests, and temperate steppes. Their generic limits have significantly changed in the last century, and past molecular phylogenetic studies of Malpighiaceae have not tested the morphological characters of this group to identify synapomorphies supporting these clades/genera. Material and methods – We sampled the monospecific Cordobia and Gallardoa, one species of Mionandra (out of 2 spp.), nine species of Peixotoa (out of 29 spp.), and a single species of Camarea and Janusia as outgroups. Bayesian and Maximum Likelihood analyses were carried out for this clade based on five molecular markers (i.e. ETS, ITS, PHYC, matK, and ndhF). A set of 16 macromorphological characters was scored and coded for identifying synapomorphies under the Maximum Likelihood criteria. Key results – Our molecular phylogeny recovered Peixotoa as monophyletic and sister to the clade comprising Cordobia + Gallardoa + Mionandra, strongly corroborating previous phylogenetic studies of Malpighiaceae. The character-mapping analyses recovered two synapomorphies supporting the Cordobia + Gallardoa + Mionandra + Peixotoa clade, six supporting Mionandra s.l. (i.e. Cordobia + Gallardoa + Mionandra), and five supporting Peixotoa. Cordobia and Gallardoa are proposed as synonyms of Mionandra, alongside the necessary combinations, typifications, and identification keys. Conclusions – Morphological characters related to the degree of connation of the stipules, leaf indumentum type, petiole length, inflorescence architecture, number of flowers per inflorescence, presence of a peduncle in the 1-flowered cincinni, sepal connation, posture and texture, petal width and margin integrity, staminode presence, shape and size, and the shape of the apex of styles were key in circumscribing these lineages. Mionandra s.l. is proposed and characterised, including a new combination, an identification key to distinguish its species, a distribution map, and taxonomy notes.

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DOI: 10.5091/plecevo.106696

Authors: Marie Claire Veranso-Libalah, Chen Luo, Ehoarn Bidault

Abstract: Background and aims – Within angiosperms, vivipary has been reported in less than 0.1% of all species. We herein report the first occurrence of vivipary in an Afrotropical Melastomataceae and discuss its phylogenetic position, habit, habitat, and fruit attributes. Material and methods – Observational data were gathered from a field expedition to Gabon, and from herbarium specimens from BR, BRLU, P, and WAG. A phylogeny was generated to map all the eight species exhibiting vivipary in Melastomataceae. Key results – Amphiblemma ciliatum is currently the only known melastome species in the Afrotropics exhibiting vivipary. It is likely that its angular capsules depend on rainwater for seed dispersal. Conclusion – The combination of a herbaceous habit and angular fruits with the occurrence on shaded humid tropical rainforest floor during periods of incessant rainfall and high humidity might be responsible for vivipary in most Melastomataceae.

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DOI: 10.5091/plecevo.105762

Authors: Karolina Fučíková, Melissa Taylor, Louise A. Lewis, Brian K. Niece, Aleeza S. Isaac, Nicole Pietrasiak

Abstract: Background – Green algae are a diverse group of photosynthetic eukaryotes, yet are still vastly understudied compared to land plants. For many years, green algae were characterized based on their morphology and life cycles. More recently, phylogenetic and genomic analyses have been added to the phycological toolkit for a better understanding of algal biodiversity and evolutionary history. Material and methods – A desert strain of green algae was isolated from Joshua Tree National Park (JTNP) in southern California as part of a larger biodiversity survey. The alga’s nuclear rRNA genes as well as the chloroplast genome were sequenced, annotated, and analysed in addition to a morphological assessment. Results – Morphologically this strain is especially similar to Pseudomuriella and Rotundella, and its lipid profile resembles that of other soil algae, but phylogenomic analyses demonstrate that it is a distinct evolutionary lineage in Chlorophyceae. The alga exhibits several unusual genomic features, the most remarkable being its highly derived yet apparently functional nuclear rRNA genes, 18S and 28S. Both genes are GC-rich and bear many compensatory base changes to maintain a similar secondary structure to that of other green algae. The chloroplast genome has a distinct gene order and repeat arrangement from other published green algal plastomes, but contains the expected genes and also provides phylogenetically informative data. Conclusion – We conclude that the strain be placed into a new species and genus in the class Chlorophyceae, and propose the name Johansenicoccus eremophilus for this new taxon. Johansenicoccus eremophilus exemplifies science’s insufficient understanding of the range of genomic variations among inconspicuous soil algae.

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DOI: 10.5091/plecevo.103395

Authors: Rafaela Sales Pereira Roxo, Maria Regina de Vasconcellos Barbosa

Abstract: Background and aims – Malanea (Rubiaceae) is a Neotropical genus of ca 40 species, 15 of which occur in Brazil, with nine found in the Atlantic Forest domain. This study aims to present a taxonomic treatment of the species occurring in the Atlantic Forest domain. Material and methods – We studied collections deposited in 15 Brazilian herbaria, ALCB, BHCB, BHZB, CEPEC, HUEFS, HUFU, IPA, JPB, MAC, OUPR, PEUFR, RFA, RB, UFP, and UFRN, and collections in NY were studied online. Specimens were identified using protologues and digital images of types available online. Key results – Of the nine species of Malanea previously recognized in the Atlantic Forest domain, we accepted seven, six of which are endemic. Malanea macrophylla has a wide distribution also occurring in other Brazilian phytogeographic domains, and adjacent countries. We expanded the distribution of four species and identified Bahia as the possible centre of diversity for the group in the domain. In addition, an identification key to the species, detailed descriptions, taxonomic notes, typifications, illustrations, maps of geographic distribution, and assessments of conservation status are provided. The names Malanea evenosa, M. forsteronioides, M. macrophylla, M. martiana, and M. spicata are here typified. The calculated conservation status revealed three Endangered species, two Vulnerable ones, M. forsteronioides as Near Threatened, and M. macrophylla with a status of Least Concern.

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DOI: 10.5091/plecevo.85589

Authors: Toral Shah, Fandey H. Mashimba, Haji. O. Suleiman, Yahya S. Mbailwa, Vincent Savolainen, Isabel Larridon, Iain Darbyshire

Abstract: Background and aims – Ochna holstii and its allies represent an ecologically important group in a variety of lowland to montane habitats in tropical eastern and southern Africa. Identifying and delimiting species within this group has proved challenging due to a lack of variation in morphological characters. We combine genomic-scale data of multiple accessions per species with morphological data to generate a taxonomic revision for the Ochna holstii complex using a multi-evidence approach. Material and methods – A total of 50 samples representing eight species were analysed using target enrichment and a custom bait kit. Phylogenetic analysis was conducted using the multi-species coalescent model and a concatenation maximum likelihood method, and gene tree discordance was investigated. Herbarium specimens of the O. holstii complex were studied in detail for informative morphological characters, supplemented where possible from field collections, and a full taxonomic revision is provided. Key results – Within Ochna sect. Schizanthera Clade I, our study confirms that all species are monophyletic and supported by morphological data with the exception of O. holstii, which is paraphyletic. A new species, O. mchanga, previously confused with O. polyneura, is described, and the placement of another recently described species, O. maguirei, is confirmed for the first time using molecular data. Conclusion – The widespread montane tree Ochna holstii is non-monophyletic in its current circumscription and likely gave rise to the more range-restricted O. oxyphylla and O. stolzii. We suggest that an integrated taxonomy approach, using both molecular and morphological data, is essential for deciphering difficult species relationships in Ochna.

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DOI: 10.5091/plecevo.101135

Authors: Rafael Felipe de Almeida, Marco O.O. Pellegrini, Isa L. de Morais, Rosangela Simão-Bianchini, Pantamith Rattanakrajang, Martin Cheek, Ana Rita G. Simões

Abstract: Background and aims – Keraunea is a Brazilian endemic genus that has sat uncomfortably in Convolvulaceae where it was placed due to an enlarged and adnate fruit bract typical of Neuropeltis. A recent molecular phylogeny suggested that two of its five morphologically almost identical species actually belong to two different families, Malpighiaceae (superrosids) and Ehretiaceae (superasterids). Later studies have demonstrated that Keraunea effectively belongs to Ehretiaceae, but the proposal of one species belonging to Malpighiaceae has remained problematic. In this study, we re-assess this hypothesis, discuss the issues that have led to this assumption, and offer insights on the importance of carefully using herbarium collections and incorporating morphological evidence in systematic studies. Material and methods – Sequences of matK, rbcL, and ITS for all 77 currently accepted genera of Malpighiaceae, K. brasiliensis and Elatinaceae (outgroup) were compiled from GenBank and analysed with Maximum Likelihood and Bayesian Inference criteria for nuclear, plastid and combined datasets. Additional database and herbarium studies were performed to locate and analyse all duplicates of the holotype of K. brasiliensis to check for misidentified or contaminated material. Key results – Our examination of expanded DNA datasets and herbarium sheets of all K. brasiliensis isotypes revealed that a mistake in tissue sampling was, in fact, what led to this species being proposed to belong in Malpighiaceae. Kew’s isotype had a leaf of Malpighiaceae (likely Mascagnia cordifolia) stored in the fragment capsule, which was sampled and sequenced instead of the actual leaves of K. brasiliensis. Recently published studies have settled the placement of Keraunea in Ehretiaceae (Boraginales) and proposed three additional species. Conclusions – DNA sequences can be helpful in classifying taxa when morphology is conflicting or of a doubtful interpretation, with molecular phylogenetic placement being established as a popular tool accelerating the discovery of systematic relationships. Nonetheless, molecular techniques are also susceptible to methodological mistakes, which necessitates building a solid foundation of plant morphology and taxonomy to avoid artefacts in phylogenetic studies.

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DOI: 10.5091/plecevo.101027

Authors: Bruno Francisco Sant'Anna-Santos, Rafael Micheli, Luiz Fernando Lima Carvalho, Patrícia Soffiatti

Abstract: Background and aims – This study is part of ongoing research on the Arecaceae Flora of the Serra do Cabral, an isolated massif in the southwest of the Espinhaço Range in Minas Gerais State. Because of the isolation of the massif, the area has a rich biodiversity and a high level of endemism. While searching for populations of the rare and critically endangered Syagrus cabraliensis, a new bluish-leaved palm species was discovered and it is described here. Material and methods – The new species’ morphology is described based on field collections. The pinnae were analysed using SEM and LM cross- and longitudinal sections following default methodology. In addition, we compared the species to S. cabraliensis and provided ecological notes and a conservation status assessment. Key results – Syagrus carvalhoi resembles S. cabraliensis but they can easily be distinguished by morphoanatomical characters. Both species occur non-sympatrically in the Serra do Cabral, in contrasting microhabitats: S. carvalhoi in the southern quartzitic campos rupestres and S. cabraliensis in the northern ferruginous campos rupestres. A key to the known grass-like Syagrus species from the massif is provided. Based on the restricted area of occurrence and the anthropogenic threats, Syagrus carvalhoi is assessed as critically endangered. Conclusion – Syagrus carvalhoi is the second grass-like endemic Syagrus species from the Serra do Cabral and presents rare characters within the genus (grass-like aspect, colonial habit, flowers in tetrads, and the stem forking at or below the ground). This discovery corroborates that this isolated OCBIL is a home for endemic and rare palm species. The Serra do Cabral massif has proved a source of morphological and anatomical novelties in Arecaceae, affecting the taxonomy and understanding of the evolution and ecology of palms. Our results reinforce the notion that it is important to conserve this area with rich and rare biodiversity but under alarming and unprecedented threats.

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DOI: 10.5091/plecevo.97453

Authors: Martin Xanthos, Simon J. Mayo, Isabel Larridon

Abstract: Background and aims – The Cyperus margaritaceus-niveus complex is a group of ten tropical species from sub-Saharan Africa and Madagascar: C. karlschumannii, C. kibweanus, C. ledermannii, C. margaritaceus, C. niveus, C. nduru, C. obtusiflorus, C. somaliensis, C. sphaerocephalus, and C. tisserantii. They are characterised by a capitate head of white-yellow spikelets and modified culm bases and recent molecular analysis puts them in a distinct clade. The group lacks a modern taxonomic revision, and the taxa described in the Flora treatments of the past 50 years differ considerably in their circumscription. In this study, morphometric analyses are used to test species limits to establish more stable morphological delimitations of the taxa. Material and methods – An examination of 15 morphological characters on 489 herbarium specimens was carried out and the data was analysed using Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA) with cross-validation, and Classification and Regression Tree (CART) analysis. Cyperus kibweanus was not further considered due to lack of material. Key results – Both PCA and LDA showed varying degrees of overlap in the nine remaining taxa, with no single group clearly separating in multivariate space. However, cross-validation clearly showed C. margaritaceus as a distinct entity despite its overwhelming presence in the PCA. Both LDA and CART failed to separate C. niveus as a distinct group as its specimens were dispersed among the other groups. Differing results were obtained for other taxa depending on the type of analysis. Cyperus margaritaceus, C. nduru, and C. sphaerocephalus were divided into two groups by CART but re-examination of the specimens does not definitively support the idea that these infraspecific groups represent separate taxa. Conclusions – The results show that eight morphospecies are recognised by LDA and six morphospecies by CART. Characters used to separate the taxa in Flora treatments scored high loadings in the analysis showing their high taxonomic utility value. The methods used can be applied to resolving other complexes in the Cyperaceae.

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DOI: 10.5091/plecevo.96359

Authors: Ehoarn Bidault, Archange Boupoya, Davy U. Ikabanga, Igor Nguimbit, Nicolas Texier, Rolf Rutishauser, Attila Mesterházy, Tariq Stévart

Abstract: Background and aims – Podostemaceae is a family of strictly aquatic plants found in rapids and waterfalls. Despite a recent treatment in the Flore du Gabon, the family remained poorly known, with no major studies including Gabonese collections, and almost no targeted inventories since 1966. We present the first large-scale inventory of this family in Gabon, targeting Podostemaceae throughout the country, providing new additions to the flora of Gabon and many new records of poorly known species. Material and methods – Fieldwork was conducted in Gabon between 2017 and 2021. The collected specimens were primarily preserved in ethanol with associated silica gel-preserved material and photographs. Material available at BR, BRLU, LBV, MO, P, WAG, and Z/ZT was examined. For each species, information on distribution and ecology is presented, as well as a distribution map in Gabon. Key results – The 500 newly collected specimens represent 91.4% of all known collections of Podostemaceae from Gabon. Three taxa are newly recorded for the country, including one genus (Inversodicraea tenax, Ledermanniella schlechteri, and Saxicolella nana). New distribution records are also presented for 13 little-known species. Four taxa are excluded from the Gabonese flora (the genus Dicraeanthus, Inversodicraea ledermannii, Ledermanniella sanagaensis, and Macropodiella garrettii). To date, 20 species belonging to five different genera are known to occur in Gabon. A new combination is proposed for Ledermanniella nicolasii, and Inversodicraea tanzaniensis is now considered as a synonym of Inversodicraea tenax.

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DOI: 10.5091/plecevo.89764

Authors: Alejandro Torres-Montúfar, Hilda Flores-Olvera, Heriberto Ávila-González, Arturo Castro-Castro, Helga Ochoterena

Abstract: Background and aims – Ongoing studies on Mexican Rubiaceae revealed an undescribed species of Coutaportla endemic to the Sierra Madre Occidental pine-oak forests in the state of Sinaloa, near the border with Durango, Mexico. The species is here described and illustrated, and its morphological characters are compared with those of the other species in the genus. Material and methods – This study is based on field observations, examination of herbarium specimens including digital images, and morphological studies based on samples from dried and spirit specimens. Key results – The morphological comparison of taxonomically important characters among the species of Coutaportla reveals conditions that were previously not reported for the genus. The placentation and ovule number of C. lorenceana, which belongs in the Portlandia complex, is comparable to that in the Chiococceae tribe. This tribe was proposed to include the latter complex based on molecular data, but the classification was controversial according to the morphology. Coutaportla lorenceana hence provides a morphological link between the Portlandia complex and the taxa traditionally placed in Chiococceae. The new species is assessed as Critically Endangered following the IUCN Red List criteria.

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DOI: 10.5091/plecevo.84606

Authors: Alexander Vrijdaghs, Petra De Block, Karen L. G. De Toni, Erik Smets, Elmar Robbrecht

Abstract: Background – Vegetative and fruit characters of the Amazonian genus Dialypetalanthus point to a position in Rubiaceae. However, its floral morphology is so deviant that the genus was often placed in a family of its own. Even relationships outside Gentianales were postulated. Current molecular phylogenetic studies firmly show that Dialypetalanthus belongs to Rubiaceae. Aims – This study aims to understand the idiosyncratic floral morphology in Dialypetalanthus and to compare it with the floral development in two other Condamineeae genera as well as in other Rubiaceae for which ontogenetic data are available. Material and methods – SEM and LM based floral ontogeny in Dialypetalanthus fuscescens, Mussaendopsis beccariana, and Pogonopus exsertus. Results and main conclusions – Flowers in Dialypetalanthus develop a stamen-corolla-calyx tube, which can be considered as a floral morphological link between the genus and the other Rubiaceae. The polyandrous androecium originates from an annular intercalary meristem at the adaxial side of the stamen-corolla-calyx tube.

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DOI: 10.5091/plecevo.94921

Authors: Thales Silva Coutinho, Mariela Analía Sader, Andrea Pedrosa-Harand, Marccus Alves

Abstract: Background – Waltheria marielleae is a new species of Malvaceae endemic to north-eastern Brazil that occurs only in the states of Pernambuco and Alagoas, in areas of Atlantic Forest and Caatinga. It is characterized by cinereous leaves, axillary and sessile to subsessile inflorescences, pallid yellow corollas with apically eciliate petals and fan-plumose stigmas. Material and methods – DNA was extracted from leaf tissue and the markers matK, ndhF, and ITS were amplified using universal primers, with PCR products purified and sequenced. Phylogenetic analysis was performed, including DNA sequences obtained from GenBank. Morphological studies were based on the analysis of specimens deposited in seven herbaria and specimens collected in Pernambuco state, Brazil. Results – Waltheria marielleae is morphologically and phylogenetically related to pantropical W. indica and W. ackermanniana, with these three species forming a well-supported clade. Overall, phylogenetic molecular analysis suggests the monophyly of Waltheria, with the two currently proposed sections also being monophyletic, and Melochia as its sister group. The new species is assessed here as Endangered, according to IUCN criteria. In addition, we formally present new occurrences of W. ackermanniana and W. rotundifolia. Conclusion – In this study, a complete morphological description, illustration, distribution map, and phylogenetic tree are provided for Waltheria marielleae. This species is compared with morphologically and phylogenetically related species (W. ackermanniana, W. indica, and W. rotundifolia) and an identification key to the species occurring in Alagoas and Pernambuco is provided.

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DOI: 10.5091/plecevo.94326

Authors: Andressa Cabral, Renato Albuquerque Magri, Jenifer de Carvalho Lopes

Abstract: Background and aims – Two new species of Vellozia (Velloziaceae) are here described and illustrated, Vellozia albohexandra and V. mellosilvae. These new species are morphologically similar to Vellozia armata, V. luteola, and V. inselbergae, probably belonging to the same informal group. Material and methods – Morphological and anatomical descriptions were based on herbarium specimens and in situ observations. Standard taxonomy and plant anatomy practices and methods were applied. Key results – Vellozia albohexandra can be easily distinguished from the other species of the group of V. luteola by its sessile flowers with white and smaller petals and sepals, six stamens, and smaller style and stigma. The species is endemic to the Cristália municipality, Minas Gerais state, and has been classified as Data Deficient according to IUCN criteria. Vellozia mellosilvae shares morphological affinities with V. armata, but it is distinguished by the leaves with serrate margin and abaxial furrows, longer and evident pedicel, and larger petals and sepals. This species is endemic to the Itacambira municipality, and should be considered Critically Endangered.

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DOI: 10.5091/plecevo.84548

Authors: João Carmo, André Scatigna, Gustavo Shimizu, André Simões

Abstract: Background and aims – Mitracarpus semirianus, an overlooked new species from the “campo rupestre” of the Chapada Diamantina, in the state of Bahia, northeastern Brazil, is here described and illustrated. Specimens of the new species have been previously identified as M. frigidus or M. lhotzkyanus, with which its distinction is discussed. We also provide an updated description of the latter, with notes on its type specimens. In addition, we comment on the distribution, habitat, and preliminary conservation status of both M. semirianus and M. lhotzkyanus. We also provide an updated identification key to the species of Mitracarpus occurring in Brazil.Material and methods – This study was based on fieldwork collections and observations and analysis of specimens deposited in herbaria. Preliminary conservation status assessments follow the IUCN Red List criteria.Key results – Mitracarpus semirianus differs from M. frigidus and M. lhotzkyanus by its glabrous stems, winged at each angle, wing margin hirsute, glabrous leaf blades, and the oblongoid and slightly compressed seeds, with a smooth longitudinal groove dorsally and an inverted “Y”-shaped groove ventrally. The new species is assessed as Endangered according to the IUCN criteria. Furthermore, it is more likely that Riedel, not Lhotzky, collected the original material of the name M. lhotzkyanus. This species is glabrate, not completely glabrous, presenting a generally strigose indumentum on the stems, stipular sheaths, and leaf blades.

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DOI: 10.5091/plecevo.84486

Authors: María Aguilar-Morales, Helga Ochoterena-Booth, Teresa Terrazas

Abstract: Background and aims – The neotropical tribe Hamelieae currently includes 16 genera mainly characterized by raphides, ebracteolate inflorescences, and 4-merous flowers with contorted corolla aestivation. Within this tribe, the circumscription of Deppea has been particularly controversial, as depending on the authors, several morphologically closely related genera are either treated as synonyms or accepted as such. This generic group, hereafter referred to as the Deppea complex, consists of up to 10 genera. Within Rubiaceae, seed morphology has proved to have taxonomic value for generic circumscriptions, however, it remained unexplored for Hamelieae and the Deppea complex.Material and methods – We present a detailed study of the seed morphology of 37 species representing 15 out of the 16 genera recognized within Hamelieae, including all putative genera of the Deppea complex. Using scanning electron and light microscopy, we investigate 16 quantitative and qualitative seed characters that could have taxonomic value.Key results – Our results show that the combination of some seed characters, such as shape and colour, dorsiventral compression, hilum position, and the periclinal microrelief, helps to distinguish some genera and most species, supporting or refuting the current taxonomic circumscription.Conclusion – We conclude that the seed morphology within Hamelieae has taxonomic value but should be combined with other characters to achieve unequivocal delineation of the genera.

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DOI: 10.5091/plecevo.84524

Authors: Ana L. Martínez-García, Claudia T. Hornung-Leoni, Irene Goyenechea Mayer Goyenechea, Julian Bueno-Villegas, Carolina Granados Mendoza

Abstract: Background and aims – A linear morphometric analysis of three taxa of the Tillandsia erubescens complex, composed of T. erubescens var. arroyoensis, T. erubescens var. erubescens, and T. erubescens var. patentibracteata, is presented to evaluate their circumscription. Additionally, their taxonomic rank as varieties or species is discussed considering the obtained results. Geographic distribution, the influence of climate, elevation, and geographic distance on morphological differences between the taxonomic entities is explored.Material and methods – Of a total of 110 herbarium specimens reviewed, 44 were measured. These were previously identified as T. erubescens var. arroyoensis, T. erubescens var. erubescens, or T. erubescens var. patentibracteata. Factor and cluster analyses were performed using 16 quantitative morphological characters. The resulting groups were considered as taxonomic entities supported by morphometric characters, and species distributions were plotted against Mexican biogeographic provinces. A single Mantel test was performed to evaluate the correlation between morphology and climatic variables, elevation, and geographic distance.Key results – The specimens referred to as T. erubescens var. arroyoensis were separated morphometrically from the other two varieties. The most important characters to differentiate T. erubescens var. arroyoensis from T. erubescens var. erubescens were total size, width and length of the leaf sheath and leaf blade, and the number of flowers. The non-overlapping geographical distribution of T. erubescens var. arroyoensis and T. erubescens var. erubescens supports their recognition as independent taxonomic entities. Our study did not support the separation between T. erubescens var. erubescens and T. erubescens var. patentibracteata, which is also reflected by their overlapping geographic distributions. Both precipitation and geographic distance were correlated with the morphological differences among the species.Conclusion – Our morphometric and geographical distribution study supports the recognition of T. arroyoensis and T. erubescens as different species, while no evidence was found to maintain T. erubescens var. erubescens and T. erubescens var. patentibracteata as different taxonomic entities. We provide a set of morphological characters that can be used to distinguish between T. arroyoensis and T. erubescens, including the leaf sheath and leaf blade width, and the number of flowers. Morphological characters agree with the geographic distribution of the studied taxa.

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