DOI: 10.5091/plecevo.196693

Authors: Mark Arcebal K. Naive, Donnafe J. Ancheta, McArthur Cababan, Eddie P. Mondejar, Harold O. Buenvenida, Mark Hughes, Wen Bin Yu

Abstract: Background and aims – The Philippine archipelago harbours the world’s greatest diversity of flowering plants, yet it is identified as a global plant diversity darkspot where much of this diversity remains poorly documented and inadequately sampled. To address this knowledge gap, extensive botanical explorations have been conducted, leading to the discovery of three new Begonia species from Panay and Mindanao Islands, which are described and illustrated herein. Material and methods – All morphological descriptions and measurements are based on recently collected living and herbarium specimens. The new species are included in a phylogenetic analysis based on noncoding plastid regions (ndhA intron, ndhF-rpl32 spacer, and rpl32-trnL spacer) and the nuclear internal transcribed spacer (nrITS) region from the assembled plastome and nuclear ribosomal DNA sequences. Key results – The newly described species from Mindanao (Begonia absiana sp. nov. and B. amorosoana sp. nov.) exhibit close morphological similarities to B. acuminatissima, while the novel species from Panay (B. panayica sp. nov.) shows affinity to B. biliranensis. The phylogenetic analyses confirmed the monophyly of B. sect. Baryandra but revealed significant cytonuclear discordance and unresolved relationships within the group. All three new species were placed in a well-supported clade, but their precise relationships remain uncertain, possibly reflecting rapid diversification. Conclusion – These findings underscore an urgent need to intensify botanical exploration and conservation efforts in the Philippines to protect these unique evolutionary lineages before their habitats are lost.

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DOI: 10.5091/plecevo.195615

Authors: João Farminhão, André Carapeto, Alejandro Alonso, Mario Fernández-Mazuecos, Llorenç Sáez

Abstract: Background and aims – The detection on the citizen science platform iNaturalist of an undescribed Linaria from the Monchique Igneous Complex (southwestern Portugal) prompted a reappraisal of the Iberian clade of L. subsect. Versicolores in the Algarve, in relation to the region’s complex geological diversity. Material and methods – The new species hypothesis was investigated using an integrative approach, combining phylogenomics based on genotyping-by-sequencing (GBS) data with a near-comprehensive revision of herbarium material and citizen science data of L. subsect. Versicolores from the Algarve. Geomorphogroups were identified based on geospatial analysis of distribution records and geological maps. Key results – Linaria alfercensis sp. nov. is part of a newly recognised, fully supported subclade endemic to the Algarve, together with L. algarviana and L. bimaculata. The new species is mostly confined to soils derived from nepheline syenites on the southern slopes of Serra da Picota, being preliminarily red-listed as Endangered. The other two members of the Algarvian subclade are near-endemic to the ‘Plio-Pleistocene sand archipelago’ of the Algarve. Two geomorphogroups of L. algarviana were identified, and the Albufeira and Cacela Gaps mostly define the western and eastern limits of the range of L. bimaculata, respectively. Geomorphogroups of L. spartea occur on Quaternary sands, the Triassic Silves Sandstone Line and some shales of the South Portuguese Zone. Linaria cf. viscosa is possibly confined to the aeolian sands of the Guadiana river mouth. Conclusion – The Iberian clade of Linaria subsect. Versicolores includes at least ten species. In the Algarve, limestone and other basic rocks, along with fine sands, shales, and greywackes, appear to function as edaphic barriers for this clade, while sandstone and coarse sand basins, igneous rocks, and aeolian sand plains represent edaphic habitat islands. This distribution pattern, associated with shifts in corolla colour and shape, denotes the role of geographical isolation and inferred edaphic specialisation in cladogenesis within L. subsect. Versicolores.

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DOI: 10.5091/plecevo.189916

Authors: Iasonas Nikolopoulos, Kit Tan, Lucie Kobrlová, Ioannis-Dimosthenis S. Adamakis, Pepy Bareka, Martin Duchoslav, Panayiotis Trigas

Abstract: Background and aims – The genus Allium exhibits extensive diversification in the Mediterranean Basin, where insular endemism and polyploidy have played a significant role in species evolution. During taxonomic and biosystematic studies of A. sect. Codonoprasum, an undescribed species was discovered on the volcanic islands of Milos and Antimilos (Kiklades, Greece). This study aims to determine its taxonomic status and phylogenetic relationships using an integrative approach. Material and methods – The new species was investigated using comparative morphology, leaf anatomy, karyological analyses, genome size estimation by flow cytometry, and phylogenetic reconstruction based on nrITS sequence data. These data were compared with those of closely related species, particularly A. occultum, as well as other representatives of A. sect. Codonoprasum from Europe and the Mediterranean region. Key results – Allium erimomeli is described here as a new species. Karyological and flow cytometric analyses revealed a hexaploid chromosome complement (2n = 6x = 48) with a mean genome size of 46.2 pg. Phylogenetic reconstruction recovered the species as a strongly supported clade sister to the tetraploid A. occultum. Despite their close phylogenetic relationship, the two taxa differ in ploidy level, genome size, and diagnostic morphological characters, primarily relating to the bulb, leaves, and ovary. Additional differentiation is supported by leaf anatomy. Morphological characters were also compared with those of A. sibthorpianum and A. rumelicum. Conclusion – The recognition of A. erimomeli as a distinct species emphasizes the significance of polyploidy and insular isolation in the diversification of A. sect. Codonoprasum in the Aegean region. These findings further enhance our understanding of evolutionary relationships within the section and call for expanded phylogenetic and cytogenetic sampling across the eastern Mediterranean region.

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DOI: 10.5091/plecevo.178054

Authors: Alejandro Ordorica-Velarde, Brenda Díaz-Cárdenas, Miguel Angel Muñiz-Castro, Patricia Castro-Félix, Eduardo Ruiz-Sánchez, J. Antonio Vazquez-García, Anne Santerre

Abstract: Background and aims – Species delimitation using multilocus coalescent-based methods has provided new insights into evolutionary processes and species boundaries. In this study, we applied a multilocus, multispecies coalescent framework to investigate species limits and estimate divergence times within the Magnolia pacifica complex, a group of endemic species from western and north-western Mexico traditionally classified based on morphological and ecological traits without explicit statistical evaluation. Material and methods – We obtained sequences of three chloroplast intergenic spacers (trnT-trnL, rpl32-trnL, trnH-psbA) and three nuclear genes (LFY, PHYA, AGT1) from 67 individuals representing all six described species and the closely related Magnolia iltisiana. Phylogenetic reconstructions were performed using Bayesian inference and maximum likelihood. Divergence times were estimated using the RelTime-ML algorithm. Species delimitation was conducted under the multispecies coalescent model using Bayesian Phylogenetics and Phylogeography (BPP) with algorithms A10 and A11. Key results – Our analyses confirm the monophyly of the M. pacifica complex within Magnolia sect. Magnolia and integrate M. iltisiana into the complex. Divergence of the complex was dated to 1.27 million years ago. Species delimitation analyses revealed five separately evolving lineages: M. pacifica (including M. talpana), M. iltisiana, M. pugana (including M. granbarrancae), M. tarahumara, and M. vallartensis, and we formally synonymize M. talpana under M. pacifica and M. granbarrancae under M. pugana. Conclusion – Pronounced morphological divergence has, in some cases, occurred within genetically cohesive lineages, highlighting a pattern of incipient differentiation. Our delimitation effectively resolves the M. pacifica species complex, providing a robust phylogenetic hypothesis and a refined taxonomic framework for understanding the diversification of Mexican magnolias and for guiding conservation priorities.

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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.175775

Authors: Daniel B. Montesinos-Tubée, Cameron E.L. Dasher, Thomas Borsch, Alejandro Torres-Montúfar

Abstract: Background and aims – The newly described species Arcytophyllum leymebambense sp. nov. (Rubiaceae) from the Amazonas department of northern Peru represents an isolated lineage within the monophyletic genus Arcytophyllum. This study aims to describe its distinctive morphological features and ecological context, assess its phylogenetic position, and discuss its implications for the diversification of the genus in the Andes. Material and methods – Morphological observations were conducted on herbarium specimens and field collections from the type locality. Phylogenetic analyses were performed using nuclear and plastid DNA sequences from the tribe Spermacoceae, with particular emphasis on Arcytophyllum. Key results – Arcytophyllum leymebambense sp. nov. is morphologically distinct from its congeners by its acuminate leaf and sepal apices, hirsute-lanuginose seeds, and the presence of protective hooks surrounding the ovary. It inhabits humid, high-elevation grasslands known as “Jalca,” where it coexists with a diverse assemblage of montane species. The species appears to be endemic to the region and is currently known from only three populations. Its restricted distribution, combined with potential threats such as overgrazing and fire, supports a preliminary conservation assessment as Critically Endangered (CR). Conclusion – The discovery of Arcytophyllum leymebambense sp. nov. highlights the underestimated diversity of Andean Rubiaceae and provides evidence that Andean species form a grade within the diversification of Arcytophyllum. This pattern suggests a historical northward expansion of the lineage into the high mountains of Panama and Costa Rica.

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DOI: 10.5091/plecevo.174072

Authors: Filip Verloove, Sipke Gonggrijp, Frederik Leliaert

Abstract: Background and aims – A previously undescribed species of Medicago was discovered in Belgium. Its identification and characterization are important for understanding non-native plant introductions linked to historical human activities. Material and methods – Morphological traits of the single individual found were assessed and compared with related species. Phylogenetic analyses were conducted using nuclear ITS and GA3ox1 markers, as well as plastid matK sequences, to establish genetic relationships. Key results – Medicago peregrina sp. nov. displays a unique combination of morphological features distinguishing it from other Medicago species. Phylogenetic evidence supports its status as a novel taxon. The species was found on a disturbed riverbank of the Vesdre River in Goffontaine, Belgium, following a major flood in 2021. The species is clearly non-native to the region and is likely associated with historical wool processing activities in the valley. Genetic affinities and the origins of imported wool suggest its native range lies in the Middle East and adjacent regions, although it has not yet been documented there. Conclusion – The discovery of Medicago peregrina sp. nov. illustrates how historical trade can leave transient botanical traces and highlights the value of continued botanical surveys in disturbed habitats. This case emphasizes the need to consider historical human activity when interpreting the presence of non-native plants.

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DOI: 10.5091/plecevo.153974

Authors: Lu Tan, Meng Hu, Dan-Dan Wu, Yi-Ran Cheng, Li-Na Sha, Xing Fan, Hou-Yang Kang, Yi Wang, Ana Valdés-Florido, Hai-Qin Zhang, Yong-Hong Zhou

Abstract: Background and aims – Campeiostachys is an allohexaploid perennial genus of the Triticeae tribe (Poaceae). The allopolyploids of Triticeae are produced by interspecific hybridization of different genera. In this study, we investigate the genome origin of Campeiostachys and the relationships of some species based on phylogenetic analyses. Material and methods – Two nuclear (Acc1 and DMC1) and two chloroplast (matK and rps16) DNA regions of the species of Campeiostachys and its related genera were used for phylogenetic analyses. Key results – The Acc1 and DMC1 sequences revealed that the genome composition of all Campeiostachys species in our study is StYH, suggesting that Campeiostachys may have originated by the natural hybridization between species with StY and H genomes, as no species with Y or HY genomes have been found in the wild. The results from the chloroplast regions indicated that the maternal donor of the Campeiostachys species contains the St subgenome. In addition, phylogenetic analysis of the nuclear sequences showed that C. purpuraristata always groups with the species of the C. dahurica complex in the St, Y, or H clade, distinct from other species in the genus. Also, C. calcicola, C. kamoji, and C. tsukushiensis var. transiens are distinct yet closely related species. Conclusion – Campeiostachys species originated from the natural hybridization of the tetraploid species of Roegneria (StY) with the diploid species of Hordeum (H), with Roegneria (StY) acting as the maternal donor. Campeiostachys purpuraristata should be classified into the C. dahurica complex and treated as C. dahurica var. purpuraristata.

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DOI: 10.5091/plecevo.154789

Authors: Emerson R. Pansarin

Abstract: Background and aims – The Brazilian biomes include the world’s greatest diversity of Vanilla. This richness has required studies on species boundaries, as many taxa have been described or erroneously synonymized. This is the case for V. argentina, a species described from the Dry Chaco synonymized under V. chamissonis. While studying the diversity of Neotropical Vanilla, differences between plants from the Cerrado/Dry Chaco, the Atlantic Forest, and the Caatinga became evident. Material and methods – Descriptions of members of the Vanilla chamissonis clade, i.e. V. argentina, V. calyculata, and V. chamissonis are provided and a morphological comparison is given. An identification key and illustrations are provided. Geographic distributions and the reproductive strategies are presented. The phylogenetic relationships among the members of the V. chamissonis clade are discussed based on an ITS (nrDNA) phylogeny. Key results – Plants occurring in the Cerrado and Dry Chaco correspond to V. argentina, while V. calyculata and V. chamissonis occur in dry environments and in the Atlantic Forest, respectively. Vanilla argentina is distinguished from the other species by several characteristics, such as the size of the leaves and the flower structures, and fruit features. Vanilla argentina is self-compatible, while V. calyculata and V. chamissonis have a reproductive system based on late-acting self-sterility. All three species are assessed as Endangered. The identities of V. carinata, V. gardneri, and V. vellozii are clarified. The name V. argentina is revalidated. Conclusion – The evaluation of vegetative and reproductive characteristics of both living and dried specimens is crucial to understand the species delimitation among Vanilla. All evidence reveals that V. argentina is distinct from V. chamissonis. Vanilla chamissonis is endemic to Brazil, while V. argentina is distributed throughout Brazil, Argentina, and Paraguay. Vanilla calyculata occurs in dry regions of South and Central Americas. The Vanilla chamissonis clade comprises a lineage of three species within the Vanilla pompona group.

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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.126936

Authors: S. Robbert Gradstein, Anna Luiza Ilkiu-Borges, D. Christine Cargill, Karen Beckmann, Alain Vanderpoorten

Abstract: Background and aims – Lethocolea (Acrobolbaceae) is a small liverwort genus of seven species distributed in temperate regions of the Southern Hemisphere and on tropical mountains. The taxonomic history of the genus has been chaotic, the species were described under many different names and have been distinguished mainly based on geography. Here, we undertook a taxonomic revision of the genus based on a reassessment of morphological characters and a molecular analysis. Material and methods – Type material and additional collections from 17 herbaria were examined in the morphological study. Sequences of the rps4 chloroplast region and maximum likelihood analyses were used to reconstruct the phylogeny. Key results and conclusions – Two fully supported clades were resolved within Lethocolea lending support to the recognition of two subgenera, subgen. Lethocolea and subgen. Symphyomitra. Lethocolea congesta from Africa, and L. glossophylla and L. radicosa from America exhibited considerable morphological overlap and were not distinguishable based on rps4 sequences. The latter two species are reduced into synonymy with L. congesta, whose range spans across Africa, the Neotropics and southern South America. In Australasia, where only one species, L. pansa, is recognized, two morphotypes were found. The first one, with a smooth cuticle, wingless gemmae, and leaf cells without trigones, is identical to the type of L. pansa and occurs in Australia and New Zealand. In addition, the species is newly reported from South Africa. The second morphotype has a papillose cuticle, winged gemmae, and leaf cells with distinct trigones, and is assigned to L. javanica, which ranges across Australasia and furthermore occurs in Java and India. The recognition of these two species is supported by molecular analysis. Altogether, we recognize four species within Lethocolea, which are thoroughly described, illustrated, and keyed. We present 12 new lectotypifications.

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DOI: 10.5091/plecevo.114642

Authors: Nicha Thawara, Panida Kongsawadworakul, Piyakaset Suksathan, Santi Watthana, Thitiporn Pingyot, Vincent S.F.T. Merckx, Saroj Ruchisansakun

Abstract: Background and aims – Bulbophyllum, the largest genus in Orchidaceae, exhibits a diverse morphology in both reproductive and vegetative characters. While trait diversity and evolution has been extensively studied in Malagasy species and within the Cirrhopetalum alliance clade, the evolution of reproductive and vegetative characters at the whole level of the Asian clade remains largely unexplored. Material and methods – We reconstructed the phylogeny of approximately 11% of all Asian Bulbophyllum species using Bayesian inference and maximum likelihood estimation based on nuclear (ITS) and chloroplast (matK, psbA-trnH) DNA sequence data. This phylogenetic framework allowed us to examine the evolution of two vegetative and four floral characters through ancestral state reconstruction. Key results and conclusion – The ancestral character states of the Asian clade of Bulbophyllum include a single leaf, distinct pseudobulbs, multiple-flowered inflorescences, and lateral and dorsal sepals similar in length. One-leaved pseudobulbs evolved into two-leaved pseudobulbs multiple times. Distinct pseudobulbs gave rise to indistinct pseudobulbs twice. Multiple-flowered inflorescences shifted to solitary flowers and 2–3-flowered inflorescences multiple times, with some instances of evolutionary reversal. Lateral sepal elongation also presents a convergent evolutionary scenario.

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DOI: 10.5091/plecevo.117163

Authors: William Wayt Thomas, Pedro Joel Silva da Silva Filho, Marcelo Reginato

Abstract: Background and aims – We tested the integrity of Rhynchospora sect. Pleurostachys, understand its evolution and origins, and test the phylogenetic separation of three morphologically distinct taxa. Material and methods – We used the chloroplast marker trnL-F and the two nuclear markers nrETS and nrITS in our phylogenetic analysis. Key results – We demonstrated that R. sect. Pleurostachys is monophyletic and that the section is divided into two large clades with the early divergent species in each clade occurring outside the Atlantic Forest of Brazil. The molecular analysis also confirmed the distinctness of the three species new to science. Conclusions – Rhynchospora sect. Pleurostachys probably originated outside the Atlantic Forest but diversified there. The three taxa are described as species new to science: Rhynchospora barbosae, R. hamadryadis, and R. eremica, from the tropical semi-deciduous and deciduous forests of Bahia and Espírito Santo, Brazil, are illustrated and compared to other related species of the section.

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DOI: 10.5091/plecevo.115623

Authors: Truong Van Do, Ngan Thi Lu, Anh Tuan Le, Mai Xuan Thi Lam, Xuan Thi Trinh, Jean-Philippe Deguine, Thao Thi Hoang, Rafael Felipe de Almeida

Abstract: Background and aims – Vietnam is one of the leading diversity centres for Asian Malpighiaceae, comprising 24 accepted species and three native genera (i.e. Aspidopterys, Hiptage, and Tristellateia). During recent fieldwork towards completing the taxonomic revision of Malpighiaceae for the Flora of Vietnam, we have collected specimens from two populations that could not be placed in any of the three native genera of this family. We performed morphological and molecular phylogenetic studies to test the generic placement of those specimens. Material and methods – We sampled 27 genera (including the Asian Acridocarpus, Aspidopterys, Brachylophon, Hiptage, Stigmaphyllon, and Tristellateia, out of a total of 75) of Malpighiaceae representing all phylogenetic clades comprising paleotropical lineages (i.e. acridocarpoids, bunchosioids, tetrapteroids, malpighioids, and stigmaphylloids), the unusual specimen recently collected in Vietnam, and the two genera of Elatinaceae as outgroups. Maximum Likelihood analysis was carried out based on a molecular matrix alignment of the internal transcribed spacer marker (ITS). Comprehensive morphological analyses were also carried out based on the collected specimens and additional herbarium specimens. Key results – Our molecular phylogeny strongly supported the unusual specimen from Vietnam placed as sister to Hiptage in the tetrapteroid clade. Key morphological traits differing these Vietnamese specimens from Hiptage were identified related to the floral bud imbrication, shape, colour, posture of sepals and petals, length of stamen filaments, number of styles, and shape of mericarps, allowing the proposition of a new monospecific genus. Conclusions – Chlorohiptage vietnamensis is proposed as a new monospecific genus closely related to Hiptage but differing in several key morphological traits. A complete morphological description is provided alongside photographic illustrations and notes on its conservation, distribution, ecology, etymology, and taxonomy. Additionally, an updated identification key to the genera of the tetrapteroid clade is provided.

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DOI: 10.5091/plecevo.110352

Authors: Fabiola Soto-Trejo, Francisco Robles, Rafael Lira, Luis A. Sánchez-González, Enrique Ortiz, Patricia Dávila

Abstract: Background and aims – Endemism may be defined according to the time of origin of taxa. Neo-endemics refer to relatively recent species that have not dispersed outside their ancestral areas. In contrast, paleo-endemics refer to species of ancient origins, which are currently geographically restricted but probably were more widespread in the past. Geographically, endemism areas may also be based on the co-occurrence of more than one species. We aimed to qualitatively identify the neo-endemism and paleo-endemism of endemic Cactaceae of the Tehuacán-Cuicatlán Valley, as well as to quantitatively assess paleo- and neo-endemics areas. Material and methods – Using a dated molecular phylogeny of endemic Cactaceae, we defined paleo- and neo-endemics using an arbitrary boundary of 2.6 million years ago; we also assessed the significance of concentrations of these species using a categorical analysis of paleo- and neo-endemism. Key results – Our results showed that most endemic Cactaceae in the Tehuacán-Cuicatlán Valley arose throughout the Pleistocene, while categorical analysis indicated localised mixed- and super-endemism (including both paleo- and neo-endemics) areas. Conclusion – We suggest that paleo- and neo-endemics, as well as localised mixed-endemism areas, may have originated due to a probable high climatic stability in the Tehuacán-Cuicatlán Valley, which in addition to topographically rugged and ecologically complex zones (e.g. ecotones, isolated habitat patches) may have allowed it to function as a refuge throughout Pleistocene climatic changes, mainly promoting the speciation of neo-endemics, as well as the persistence of relatively few paleo-endemics.

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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.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.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.89701

Authors: Steven B. Janssens, Hermann Taedoumg, Steven Dessein

Abstract: Background and aims – The genus Impatiens is known for its enormous convergent phenotypic adaptation, with similar floral traits having independently evolved in distantly related lineages. The large functional convergence of Impatiens flowers causes a high degree of homoplasy for several phenotypic characters resulting in increased difficulties to distinguish between species with a similar morphology that are only distantly related, however. As a result, some species remain under the radar, as they are confused with other well-known species. This was the case for a new Impatiens species from the Tchabal Mbabo Mountains in Cameroon – Impatiens smetsiana – that was initially mistaken for the morphologically similar species I. erecticornis, an endemic from Central East Africa. Material and methods – A combined molecular-morphological approach was applied in which phylogenetics (ITS, ImpDEF1, and ImpDEF2), biogeography, and age estimation analyses were combined with morphological data on floral and vegetative structures. Key results – In this study, we demonstrate the close affinity of the newly collected material with a group of Equatorial West African species, including I. filicornu, I. nzabiana, I. oumina, and I. kamerunensis. The present finding represents a clear case of convergent evolution in which two distantly related taxa independently converged on practically the same flower morphology. Conclusion – Within Impatiens, several examples of floral homoplasy have been observed yet not in such a clear way. The convergent evolution of the flowers of I. smetsiana and I. erecticornis is undoubtedly closely correlated with an adaptation to a similar pollination syndrome.

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