DOI: 10.5091/plecevo.165188

Authors: Anneth Díaz-Reyes, Natalia Aguirre-Acosta, Carolina Feuillet-Hurtado, Ghennie Tatiana Rodríguez-Rey

Abstract: Background and aims – Ulex europaeus is an invasive allopolyploid (hexaploid) plant considered a global threat that has successfully colonized various regions, including the Northern Andes. This study aimed to assess its diversity and genetic structure in six sampling sites from the Central and Eastern Andes of the Northern Andes of Colombia, located in conservation-priority highland landscapes, using single nucleotide polymorphisms. Material and methods – Given the complex inheritance patterns of polyploids, both diploid and hexaploid datasets were analysed to estimate genetic diversity (e.g. Ho, He, FIS, and private alleles) and population structure (using e.g. FSTp, AMOVA, STRUCTURE, PCA, DAPC analyses). Additionally, the introduction history of the species in the Northern Andes, particularly the introduction from the Eastern to the Central Andes, was investigated using ABC-RF. Key results – Diploid and hexaploid datasets showed consistent clustering patterns, supporting predominantly disomic inheritance. Populations exhibited high heterozygosity (diploid: Ho = 0.302, He = 0.252; hexaploid: Ho = 0.483, He = 0.222). Genetic structure analyses showed moderate differentiation (FSTp = 0.118 for diploid; FSTp = 0.074 for hexaploid) and significant isolation by distance (diploid: r = 0.479, p value = 0.022; hexaploid: r = 0.507, p value= 0.012), but without a clearly defined spatial pattern, suggesting restricted gene flow influenced by external factors. ABC-RF analyses indicated at least two independent introduction events in the Eastern Andes, followed by multiple dispersal events into the Central Andes. Conclusion – Ulex europaeus populations in the Northern Andes maintain high heterozygosity and restricted gene flow. Polyploidy likely contributes to preserving genetic diversity, while multiple introduction events and human-mediated dispersal shape population structure, underscoring the complex invasion dynamics of this species in high-mountain ecosystems.

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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.160614

Authors: Higor Antonio-Domingues, Cynthia Fernandes Pinto da Luz, Mônica Lanzoni Rossi, Rafael Felipe de Almeida, Adriana Pinheiro Martinelli, Gwilym Peter Lewis, Ana Paula Fortuna-Perez

Abstract: Background and aims – Zornia is the only pantropical genus in the Adesmia clade (Dalbergieae), subdivided into two clades by previous phylogenetic studies. Zornia remains the only genus of the Adesmia clade to be palynologically understudied. We present a comprehensive palynological study for this genus, testing the systematic relevance of pollen morphology in a phylogenetic context. Materials and Methods – Standard acetolysis was performed on all pollen grains of the Zornia species, alongside advanced microscopic techniques (LM, SEM, and TEM). Additionally, a principal components analysis was performed to elucidate patterns of variation in quantitative data among species. Using the most recent phylogenetic framework existing for the taxa, we scored and coded 13 micromorphological characters to test for secondary homologies. Key results – A comprehensive pollen characterisation enabled a complete description of Zornia as stenopalynous, with some differences in pollen grain size and ultrastructure of the operculum, margo, and sexine. The thickness of the pollen nexine (> 0.5 μm) is considered a synapomorphy for the genus Zornia, as shown by our character reconstruction analysis. Conclusions – The presence of colpate apertures is a unifying pollen character of the genus Zornia. In addition, the thickness of the pollen nexine (> 0.5 μm) was recovered as a synapomorphy for the genus, while Zornia Clade A was supported by two homoplasies correlated with ultrasculpture of the apocolpium (psilate-perforate) and sexine thickness (< 0.5 μm) and Zornia Clade B by the exoaperture width (5–10 μm). The stenopalynous nature of Zornia pollen grains is corroborated here by the large number of homoplasies recovered.

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DOI: 10.5091/plecevo.161947

Authors: D. Jithmi M. De Silva, B.D. Punsara Dharaka, K.M.G. Gehan Jayasuriya, Filip Vandelook

Abstract: Background and aims – Climate change is a significant global challenge affecting soil health and agriculture, including increased soil salinity levels. Certain salt-tolerant wild species can be considered for crop improvement and provide a solution to increasing salinization. We studied the inter-population variation in salt tolerance of Vigna marina seedlings, to explore the potential use of these wild resources to improve cultivated Vigna and for better conservation decisions. Material and methods – Inter-populational variation in salinity tolerance of seedlings of four different V. marina populations growing in different regions in Sri Lanka (Unawatuna, Mahamodara, Negombo, and Thalpe) was studied. Seedlings from seeds collected from these populations were grown under 0, 100, 1000, 2000, 10,000, and 20,000 ppm NaCl concentrations, following standard salinity tolerance test procedures. The plant performance was evaluated by measuring biomass, root: shoot ratio, height, growth rate, and chloride ion accumulation in leaves, stems, and roots. Finally, the performance of the V. marina populations was compared with two commercial varieties of Vigna radiata (MI6 and Ari), one of which was considered salt-tolerant. Key results – All seedlings showed reduced growth at 10,000 and 20,000 ppm NaCl concentrations. The Negombo population showed the highest total dry mass at 20,000 ppm, and seedlings from all populations survived at 20,000 ppm salt concentration, except those from the Mahamodara population. Overall, the Thalpe population performed best at 20,000 ppm. The highest salt accumulation was recorded in leaves and stems rather than in roots. Commercial V. radiata varieties did not survive the highest salt concentrations (10,000 and 20,000 ppm). Conclusion – Given that V. marina populations collected in different locations show considerable inter-populational variation in salinity tolerance, we recommend conserving multiple V. marina populations to cover the range in variability in salinity tolerance traits. Natural populations of V. marina exhibited better survival at high salinity levels as compared to the commercial salt-tolerant V. radiata varieties, highlighting the halophytic nature of V. marina, and its putative importance in developing Vigna varieties that can be cultivated in more saline conditions.

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DOI: 10.5091/plecevo.138834

Authors: Alejandra Lorena Goncalves, María Victoria García, Emilie Chancerel, Olivier Lepais, Myriam Heuertz

Abstract: Background and aims – Anadenanthera colubrina is a Neotropical native forest tree species with significant ecological importance in Seasonally Dry Tropical Forests. Developing genetic markers for this species is relevant for conservation, breeding, and evolutionary studies. Previously available genetic markers for A. colubrina consisted of a few microsatellites. Next-generation sequencing (NGS) strategies allow simple and cost-effective development of new SSR loci from low-coverage whole genome shotgun sequencing. The main aim was to develop microsatellite markers for sequence-based high-throughput genotyping (SSRseq) in the species and to characterize their information content against traditional capillary electrophoresis-based microsatellite data by estimating the amount of molecularly accessible size homoplasy of each locus. Additionally, the reliability of these markers for population genetic analysis was assessed by genotyping two age classes (reproductively mature trees and seedlings) in a typical location in Argentina. Key results – Sixty primer pairs targeting microsatellites were designed, of which 25 were validated with allelic error rates < 3% and genotype missingness < 20%. A significantly higher number of alleles per locus and heterozygosity was detected for SSRseq considering sequence polymorphisms compared to analysing the same data based on sequence size (length) only. Size homoplasy, calculated as the proportion of mismatches between datasets relative to the number of alleles differing in length, averaged 97.85% over all SSR loci. High levels of population genetic diversity were detected in adults and seedlings from Paranaense forests, exceeding those reported in previous studies of A. colubrina using traditional SSRs. The generated datasets increase the resolution of capillary-based microsatellite genotyping, allowing for more accurate inference of eco-evolutionary processes in non-model tree species.

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DOI: 10.5091/plecevo.133256

Authors: Bonaventure Sonké, Murielle Simo-Droissart, Ehoarn Bidault, Fernandez Ngoula, Xander M van der Burgt

Abstract: Background and aims – For some time now, the forests of the Sanaga basin in Cameroon have been threatened by the construction of numerous hydroelectric dams. In anticipation to this construction work, botanical surveys were carried out, resulting in the discovery of many species new to science. One of these certainly belongs to the genus Talbotiella in Leguminosae. Material and methods – This study is based on morphological observations on herbarium specimens, through detailed examination of 28 specimens of the new tree species as well as specimens of existing species of Talbotiella. Key results – Talbotiella couteronii is described and illustrated. The new species resembles Talbotiella batesii but has fewer leaflets, 5–10 pairs; an inflorescence usually with fewer flowers, 5–12; and flowers with longer pedicels, 10–20 mm long. Talbotiella couteronii is endemic to Cameroon, where it is restricted to the middle Sanaga basin in the Central Region and the Littoral Region. It occurs gregariously in periodically flooded riverine forests. Talbotiella couteronii is preliminarily assessed as Endangered following the IUCN Red List categories and criteria. The genus Talbotiella now consists of 10 species; of which six species are endemic to Cameroon. A comparative table summarizes the main vegetative characteristics of the 10 species. This treatment also includes an update of the description of T. bakossiensis.

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DOI: 10.5091/plecevo.122470

Authors: Gbèwonmèdéa Hospice Dassou, Gafarou Agoundé, Pathmos Akouété, Gnimansou Abraham Favi, Ghyslain Chabi Kpétikou, Kolawolé Valère Salako, Jéronime Marie-Ange Sènami Ouachinou, Judicael Makponsè, Amadou Malé Kouyaté, İdris Sari, Romain Lucas Glèlè Kakaï, Hounnankpon Yédomonhan, Aristide Cossi Adomou

Abstract: Background and aims – Climate change induces increasing temperatures and drought, with possible profound shifts in species’ presence and distribution. Ecological niche models are widely used to assess plant species responses to climate change. However, such data are scarce for West Africa, particularly for vulnerable multipurpose species. This study focuses on modelling the ecological niche and the conservation status of the multipurpose tree Detarium senegalense to improve insights into its habitat suitability in West Africa under past, present, and future climatic conditions. This will provide an essential basis for setting up global management plans through efficient conservation and ecological restoration policies. Material and methods – The potential distribution of D. senegalense under past, current, and future climate scenarios were assessed using four algorithms including generalized additive models (GAM), generalized linear models (GLM), random forest (RF), and Maximum Entropy (MaxEnt). We also assessed the shift direction of suitable habitats and the conservation status of the species based on IUCN criteria. Overall, 220 occurrences were combined with a set of five bioclimatic variables to run the models. Key results – Models performed well with good values of AUC (0.92) and TSS (0.73). Isothermality (41.10%) and Precipitation of Wettest Month (21.50%) contributed most to the distribution of the species. The distribution of D. senegalense was relatively constant from the past to the present but could decrease in the next decades. In the future, only 17.70% and 13.98% of the areas were predicted to be suitable under respectively ssp245 and ssp585. In protected areas, the suitable areas under ssp245 were estimated at 21.01% with a decrease of 2.50% and 14.60% with a decrease of 8.61% under ssp585 by 2050. The direction of the distribution shifted to the south-east under future climate scenarios. The conservation status assessment of the species is Least Concern (LC). Conclusion – This study improves our understanding of the past, present-day, and future distribution of the species and provides support to better manage the conservation of D. senegalense in West Africa.

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DOI: 10.5091/plecevo.120171

Authors: Charles H. Stirton, Abubakar Bello, A. Muthama Muasya

Abstract: Background and aims – Following detailed phylogenetic and biogeographic studies of the tribe Psoraleeae, the genus Psoralea L. was shown to have been derived out of Otholobium C.H.Stirt. As Psoralea has nomenclatural priority, Otholobium has been subsumed into Psoralea, whereby two broad subgeneric groups are aligned with the previous descriptions of the separate genera, but some problems of placement of a few species remain unresolved. Work is ongoing to study and describe the nearly 20 undescribed species that will have to be considered before sectional groups can be established. In this paper we describe ten new species, including several putative taxa already recognized in regional floras, based on historic specimens and more recent field collections. Material and methods – Standard practices of herbarium and field taxonomy have been applied to study herbarium material available at B, BLFU, BM, BOL, BR, E, GRA, J, JRAU, K, KEI, L, LE, LINN, M, MO, NBG, NH, NU, NY, OXF, P, PRA, PRC, PRE, PRU, S, SAM, SCHG, SRGH, TCD, Z, ZT, and US. Additional material was provided from fieldwork by the authors and collaborators. Key results – Ten new species of Psoralea from southern Africa are described: Psoralea crista C.H.Stirt. & Muasya, P. fulva C.H.Stirt. & Muasya, P. luteovirens C.H.Stirt. & Muasya, P. nubicola C.H.Stirt. & Muasya, P. oreopola C.H.Stirt., P. pallescens C.H.Stirt. & Muasya, P. papillosa C.H.Stirt. & Muasya, P. prompta C.H.Stirt. & Muasya, P. schutteae C.H.Stirt. & Muasya, and P. vlokii C.H.Stirt. & Muasya. Conclusion – The newly described species, all restricted to South Africa, increases the number of Psoralea species to 129. These species arise from expanded fieldwork into previously under-collected areas, as well as from better refinement in species delimitations in the leafless ‘aphylla’ and pinnately-leaved species complexes.

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DOI: 10.5091/plecevo.111072

Authors: Lara Serpa Jaegge Deccache, Haroldo Cavalcante de Lima, Claudio Nicoletti de Fraga

Abstract: Background and aims – The neotropical genus Tachigali comprises about 75 recorded species, including names described in Sclerolobium, synonymised in 1993 in Tachigali based on morphological, molecular, and anatomical characters. Most species are found in northern South America and the Atlantic Forest. However, some species are exclusively found in the savannas of central Brazil (Cerrado), Bolivia, and Paraguay. The Tachigali species from northern South America and Central America has already been revised. However, the extra-Amazonian Tachigali species were not correctly typified due to the impossibility of examining all syntypes. Therefore, the present work aims to present the nomenclatural review of the extra-Amazonian species of Tachigali. Material and methods – The list of accepted extra-Amazonian Tachigali names and their basionyms was made and verified through online databases. The original descriptions were consulted online or in the Rio de Janeiro Botanical Garden Library. The type specimens were examined in virtual herbaria and through visits to the B, IAN, G, K, M, NY, P, R, RB, US, and W herbaria. The International Code of Nomenclature of algae, fungi, and plants was followed for the type designation and nomenclatural notes. Key results – The nomenclatural review was carried out for 32 names. A total of 15 lectotypifications, representing 12 Tachigali species, and a new combination for Tachigali rubiginosa is proposed herein. Furthermore, the nomen dubium Sclerolobium macrophyllum is presented. Conclusion – Our study provides the nomenclatural review for the extra-Amazonian Tachigali species, including notes about the type materials, collectors, and authors of all species names, in addition to the holotype and lectotype images.

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DOI: 10.5091/plecevo.91373

Authors: Arthur F. Boom, Jérémy Migliore, Esra Kaymak, Pierre Meerts, Olivier J. Hardy

Abstract: Background and aims – Brachystegia is a species-rich tree genus found in tropical Africa and a typical element of Miombo woodlands, a widely distributed subtype of the Zambezian savanna. Plastid DNA was shown to be largely uninformative to assess species phylogenetic relationships due to widespread chloroplast capture among species. Here, we aim to assess the capacity of nuclear ribosomal DNA (rDNA) to clarify the phylogeny of Brachystegia species while accounting for intra-individual site polymorphisms (2ISPs), which are often present in rDNA and potentially phylogenetically informative. Material and methods – Genome skimming sequencing on 47 samples representing 27 of the 29 currently recognized Brachystegia species, allowed us to retrieve complete nuclear ribosomal cistrons encoding for 18S, 5.8S, and 25S rRNA genes (35S rDNA). We reconstructed the Brachystegia phylogeny using Maximum Likelihood methods based on the standard substitution model or integrating 2ISPs (GENOTYPE implementation in RAxML-NG). We additionally tested the effect of partitioning the data (one partition for rDNA genes and one for the ITS1+ITS2). We also conducted network inferences (Neighbor-Net splits graph), as a strict bifurcative approach might not properly model topological uncertainty at shallow phylogenetic depth. Key results – 2ISPs-aware and standard phylogenetic reconstructions are largely congruent. We identified several well-supported main clades clarifying the species relationships, including two clades of Miombo woodlands species. Miombo Group A includes species with ovoid to globose axillary dormant buds, while Miombo Group B species have flattened ones. Two morphologically close Brachystegia species (B. kennedyi and B. leonensis) found in Guineo-Congolian rain forests form also a robustly supported clade. 2ISPs coding allowed to identify an additional Guineo-Congolian clade (B. eurycoma and B. nigerica). Ribosomal DNA therefore proves more useful to explore the generic phylogeny than plastid DNA but the species relationships within and among the main clades remain poorly resolved, probably due to recent diversification and/or recurrent hybridization, so that the diversification of Brachystegia remains to be more properly characterised. Conclusion – Nuclear and plastid phylogenetic reconstructions of Brachystegia species are discordant. Even if not well-resolved, rDNA phylograms and networks are characterized by taxonomic sorting, while we observe a strictly geographic sorting in the plastid dataset. Most of the species’ relationships remain to be characterized using additional nuclear markers combined with in-depth morphological investigations.

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DOI: 10.5091/plecevo.84547

Authors: Olivier Lachenaud, Ehoarn Bidault

Abstract: Background and aims – The genus Englerodendron (Leguminosae-Detarioideae) has recently been enlarged to include Isomacrolobium and Pseudomacrolobium, and currently includes 18 tropical African species. The recent discovery of a new species in Gabon has led us to re-evaluate the delimitation of several taxa in the genus.Material and methods – This paper is based on field work by the authors in Gabon, and on a study of herbarium material from BR, BRLU, K, LBV, MO, P, and WAG; normal practices of herbarium taxonomy have been applied.Results – Englerodendron nguemae is described and illustrated as a new species, endemic to Gabon. It is remarkable for the variation in its leaves, which may be 2-jugate, 1-jugate, or unifoliolate on the same plant. The species is most similar to E. brachyrhachis, but the latter has uniformly 2-jugate leaves; E. nguemae also differs in its longer and more broadly winged leaf rachis (if present) that is convex (not flat) above, its stamen filaments pubescent at the base, and its glabrous style. Several collections from the Democratic Republic of the Congo, previously associated with E. obanense, are considered here to represent two different taxa. One of them, E. macranthum (a new combination and name at new rank based on Macrolobium isopetalum var. macranthum, which is raised to species status), is endemic to the Mayombe range and differs from E. obanense by its inflorescences branched from the base or nearly so, and its shorter 1-seeded pods. The other taxon, still imperfectly known and here treated as Englerodendron sp. A, is endemic to the Kivu region; it differs from E. obanense by its large foliaceous stipules and from E. conchyliophorum by the lack of a basal auricle on the stipules. In addition, the first records of E. leptorrhachis from Equatorial Guinea, and of E. conchyliophorum from the Republic of the Congo, are documented, and a revised key to the now 21 species (one undescribed) of Englerodendron is presented.

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DOI: 10.5091/plecevo.2018.1423

Authors: Alex Baumel, Pascal Mirleau, Juan Viruel, Magda Bou Dagher Kharrat, Stefano La Malfa, Lahcen Ouahmane, Katia Diadema, Marwa Moakhar, Hervé Sanguin, Frédéric Médail

Abstract: Background and aims – The thermophilous woodlands of the Mediterranean region constitute reservoirs of genetic resources for several fruit trees. Among them, the carob tree (Ceratonia siliqua) is a key component of traditional Mediterranean agroecosystems but its ecology was never assessed at the scale of its whole distribution area. Fortunately, phytosociological literature shelters invaluable resources for several issues in conservation, among them the possibility to analyse plant biodiversity at regional or continental scale. Here, we present the results of a comprehensive survey of the phytosociological literature associated to carob tree. Methods – We collected 1542 floristic relevés performed in 18 geographical areas distributed around the Mediterranean in which the presence of C. siliqua was recorded. Species composition of the plant communities was analysed by multivariate ordination and hierarchical classification, and species diversity was evaluated by rarefaction and prediction analyses of Hill numbers. Key results – Multivariate analyses revealed that plant communities associated with the carob tree are well differentiated between the Western and Eastern basins. A wider range of floristic differentiation is revealed in the Western basin where the vegetation reaches its maximal heterogeneity. By comparison, in the Eastern basin the plant assemblages associated with the carob tree are more homogeneous and with a lower species richness but a higher Simpson diversity. Conclusions – The large ecological range of the Mediterranean carob trees is potentially an important evolutionary legacy for the conservation of genetic resources and seed sourcing for new uses such as restoration ecology.

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