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.164557

Authors: Cynthia Hong-Wa, Guillaume Besnard

Abstract: Background and aims – Madagascar’s rich flora originated mostly from in situ diversification, and the large-scale plant species richness pattern is mainly explained by spatial heterogeneity. However, mechanisms underlying plant community assembly remain largely unexplored. We aimed to understand the coexistence of a species swarm in the Malagasy olive (Noronhia, Oleaceae) on the northern massif of Montagne d’Ambre and to gain insights into the factors influencing community assembly. Material and methods – We used 13 environmental and 17 trait variables sampled across 24 plots and 13 species on the mountain, respectively. We determined likely trait-environment relationships across space using the multivariate RLQ analysis, the bivariate fourth-corner method, and their combination. We also checked for phylogenetic signal (Blomberg’s K and Moran’s I) among traits and assessed the phylogenetic community structure (SES.MPD and SES.MNTD) using nested spatial and phylogenetic scales. Key results – Significant trait-environment relationships were recovered with the multivariate and the combined multi–bivariate analyses at a large spatial scale, whereas patterns at small spatial scales were unclear. Distinct assemblages at lower and higher elevations were identified and appeared to be influenced by bioclimate and soil gradients. Strong phylogenetic signals were detected in seven traits across spatial scales, regardless of phylogenetic scales. The communities exhibited an overall pattern of phylogenetic clustering with a large phylogenetic scale, while a hint of overdispersion emerged in the low-elevation assemblage with a small phylogenetic scale. Conclusion – Multiple mechanisms may influence the coexistence of the Noronhia swarm on Montagne d’Ambre, with environmental filtering and niche partitioning seemingly acting on vegetative and reproductive functions, respectively. More focus on reproductive biology will provide further insights into the assembly of Malagasy plant communities. This study also highlights the conservation values of Montagne d’Ambre as a unique ecosystem supporting the flora, fauna, and human populations of the northernmost region of Madagascar.

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DOI: 10.5091/plecevo.167734

Authors: Naim Berisha, Fadil Millaku, Elez Krasniqi

Abstract: Background and aims – The genus Pulsatilla (Ranunculaceae) comprises ecologically and biogeographically significant taxa in the mountainous regions of the Balkans. Despite its importance, the diversity and distribution of Pulsatilla taxa in Kosovo have remained poorly documented. This study provides an updated overview based on new field data and critical taxonomic assessment. Material and methods – Extensive fieldwork was carried out across various mountain massifs in Kosovo, supplemented by herbarium revisions and morphological comparisons with reference material. Elevational ranges, ecological preferences, and population data were recorded for each taxon. Key results – A total of four species comprising five taxa are confirmed for the flora of Kosovo: Pulsatilla alpina subsp. apiifolia, P. halleri subsp. rhodopaea, P. montana subsp. balkana, P. montana subsp. jankae, and P. vernalis. New distributional records are provided, including the first confirmed presence of P. halleri subsp. rhodopaea in Kosovo and P. vernalis in the Sharri Mountains. Past misidentifications of P. montana subsp. jankae as P. vulgaris subsp. grandis are corrected. Conservation assessments suggest that P. alpina subsp. apiifolia remains nationally endangered, while P. halleri subsp. rhodopaea qualifies as Vulnerable due to its restricted range and occurrence at only two sites. Conclusion – The study clarifies the taxonomy, distribution, and conservation status of Pulsatilla taxa in Kosovo. It highlights the regional importance of certain populations and underscores the need for continued monitoring and habitat protection in light of environmental pressures and climate change. These findings contribute to the broader understanding of plant diversity in the Western Balkans and support evidence-based conservation planning.

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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.101827

Authors: Rivoharifara Randrianarimanana, France Rakotondrainibe, Elodie Boucheron-Dubuisson, Lovanomenjanahary Marline, Mijoro Rakotoarinivo, Catherine Reeb

Abstract: Background and aims – In contrast to the flowering plants, the pteridophyte flora of Madagascar is still understudied. While several studies have been published on the eastern and central parts of the island, there are currently few works dedicated to the pteridophytes of southwestern Madagascar. The aim of this work is to increase the knowledge of the pteridophyte flora of the Isalo massif in southwestern Madagascar. It presents a checklist of Isalo’s pteridophytes and an analysis of the diversity and distribution patterns of pteridophyte communities across ecological gradients in the eastern canyons of Isalo. Material and methods – Eighty plots were placed in six canyons. In each plot, pteridophyte species abundance was inventoried, as well as several ecological and geomorphological variables. A census in the field and observations on specimens in herbaria were carried to make a checklist of all the pteridophyte species known for Isalo. Statistical analysis was carried out to understand the pteridophyte diversity and distribution patterns in the Isalo’s canyons: (1) exploratory analysis (FAMD and HCPC) highlights the general patterns of ecological gradients, (2) a rarefaction curve was used to compare species diversity, and (3) co-inertia analysis investigated the relationship between ecological gradient and pteridophyte communities. Key results – In total, 60 species of ferns and lycophytes have been recorded in the massif, including ten endemic species to Madagascar and 11 species reported for the first time in the Isalo massif. Species diversity is especially high in the northern canyons (Anjofo, Andramanero, Antsifotra) in contrast to the middle (Maki and Rats) and southern (Namaza) canyons. Fern distribution patterns were correlated to a combination of environmental factors, highlighting species-specific ecological preferences.

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