Higor Antonio-Domingues

A comprehensive palynotaxonomic study is presented of species of Vernonia from Madagascar, documenting 37 (out of 44) taxa using light microscopy (LM) and scanning electron microscopy (SEM). Statistical analyses were performed to explore patterns of variation in quantitative data between the species. The pollen variation is categorised into two pollen types based on qualitative and quantitative characters, which was supported by Principal Components Analysis. A mesoaperture, a unique apertural structure, is also described for the genus for the first time. Further integrative taxonomic studies focused on Vernonia and the Vernonieae tribe, including species from continental Africa and Madagascar, are ongoing and will help to determine whether these characters remain taxonomically informative and whether they could be applied in an evolutionary framework.

L'état et la diversité de la sous-tribu Monotheciinae (Acanthaceae, Acanthoideae, Justicieae) à Madagascar sont investigués grâce à des études macro- et micro- (pollen) morphologiques. Plusieurs espèces précédemment classées à titre provisoire dans les genres Isoglossa Oerst. (Isoglossinae) ou Justicia L. (Justiciinae) se révèlent mieux classées dans le genre asiatique Ptyssiglottis T.Anderson sur la base de sa circonscription actuelle. Cela constitue donc la première mention de ce genre en Afrique et à Madagascar. Parmi celles-ci figurent quatre espèces nouvelles pour la science: Ptyssiglottis antongilensis I.Darbysh., P. gracillima I.Darbysh. & L.Rapp, P. ranomafanensis I.Darbysh. et P. tsingycola I.Darbysh. & Callm. Justicia plebeia Benoist est également transférée à Ptyssiglottis sous la nouvelle combinaison P. plebeia (Benoist) I.Darbysh. & Callm. Un deuxième genre des Monotheciinae, Ambongia Benoist, s'avère être monospécifique, avec A. perrieri Benoist provenant du nord et du nord-ouest de Madagascar. Monothecium leucopterum Benoist est rejeté de la sous-tribu, car des preuves moléculaires démontrent que cette espèce appartient au clade «Anisostachya» au sein des Justiciinae. Par conséquent, nous reconnaissons actuellement six espèces de Monotheciinae à Madagascar, toutes endémiques de l'île. Received: 22 December 2025; Accepted: 27 March 2026; First published online: 17 June 2026

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.

Summary: A new genus of Convolvulaceae, Muigaia , is here proposed and fully revised, including molecular phylogenetic analyses, comprehensive morphological and palynological descriptions, identification keys, distribution maps and conservation assessments. It is a strictly paleotropical genus, occurring in Tropical Africa, Madagascar, India and Australia, and remarkably absent from the Malesian region. It is distinctive for the markedly angular stems; deeply palmately lobed, irregularly dissected leaves; leaf-like stipules at the base of the petiole; muricate, verrucose or cristate sepals; a 3-globose stigma and a 6-valved capsule. A revision of the species involved in this complex has resulted in the recognition of a total of seven species, including five new combinations, one new name ( M. shimpalei ) and one newly described species ( M. australiana ), endemic to Australia. The tropical African specimens of M. coptica , in particular, exhibit a wide range of morphological variation and should be investigated in detail. We expect that, now that Muigaia has been phylogenetically and morphologically circumscribed, further revisionary studies could focus on improving the species delimitation, and likely result in the discovery of additional new species to science.

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.

Summary: The new genus Cryptacanthus I.Darbysh. & Kiel (Acanthaceae: Acanthoideae: Justicieae: Justiciinae) is described from the Guineo-Congolian forests of West and Central Africa based on a combination of molecular phylogenetic data and macro- and micro-morphological studies. Previously referred to informally as the “Rhinacanthus virens Clade”, it comprises three species currently placed in either Justicia L. or Rhinacanthus Nees, namely J. tenuipes S.Moore, R. obtusifolius (Heine) I.Darbysh. and R. virens (Nees) Milne-Redh. for which new combinations are made, plus three species endemic to Cameroon, all of which are newly described here, namely Cryptacanthus bakossii I.Darbysh., C. ebo Cheek and C. obovatus I.Darbysh. With the exception of the widespread R. virens, for which recent accounts already exist, descriptions and illustrations are provided for all of the species, and notes on their habitat preferences, distribution and extinction risk status are provided. The new species are all considered to be Critically Endangered based upon current evidence.

Vernonia (Asteraceae: Vernonieae) is monophyletic if circumscribed to include only a North American clade of ca. 20 species. Vernonia pratensis, an endemic species of Madagascar, has been placed in the synonymy of Cyanthillium patulum or considered a distinct species in Bothriocline. In this study we characterise the pollen and cypsela of Vernonia pratensis, Bothriocline longipes, and Cyanthillium patulum with details on morphology and ultra-sculpture. The pollen grains of these species are 3-brevicolporate or 3-porate and echinolophate; in B. longipes and V. pratensis there is an inconspicuous colpus formed by interlacunar gaps (absent in C. patulum). The cypselae of B. longipes and V. pratensis have prominent ribs, broader or equally as wide as the grooves and that are fused into a shallow, apical rim; the grooves are covered by unicellular trichomes (type 1) with a striate cuticle. By contrast, the cypselae of C. patulum have ribs narrower than the grooves and not fused apically; the grooves are covered by infundibular idioblasts, and bilobed glandular trichomes at the base. Based on these morphological findings, V. pratensis is here placed in Bothriocline and named B. madagascariensis. This is the single species that occurs in Madagascar within a genus of ca. 50 species otherwise restricted to Tropical Africa and subtropical Southern Africa. Full palynological descriptions, measurements, and scanning electron microscopy (SEM) and light microscopy (LM) images are provided for the three species (B. longipes, B. madagascariensis, and C. patulum), as well as a full taxonomic description of B. madagascariensis, with a preliminary conservation status assessment, nomenclatural notes, and a discussion of possible relationships with other species of Bothriocline.

Malvales is a diverse order of flowering plants, economically and ecologically relevant, and it is known for its broad morphological variability. Recent phylogenomic studies have revealed a complex evolutionary history for the order, including localised phylogenetic discordances among nuclear loci. However, since the late 1990s, Malvales classification has largely been neglected. This study aims to address this gap by revisiting the classification of Malvales, with a focus on its largest family, Malvaceae. By integrating phylogenomic and morphological datasets, our primary goals are to provide an updated phylogeny for the order and to map key traits supporting a revised suprageneric classification, while accounting for gene and species tree conflicts. Our molecular dataset included 194 genera and 309 nuclear genes, obtained through target sequence capture using Angiosperms353 probes. This dataset covers approximately half of the known genera in the order, representing all families and subfamilies, as well as nearly all tribes, and all subtribes. A coalescent approach utilising nuclear gene trees was used to infer phylogenetic relationships. A morphological matrix with 50 characters relevant for suprageneric classification was compiled, and character‐state distributions for selected traits were mapped against the phylogenetic tree to identify and discuss diagnostic features for clades. Phylogenetic relationships and the monophyly of most groups aligned closely with previous studies. Morphological traits that define key clades varied significantly across Malvales, with differences observed in growth habit, leaf structure, pollen type, floral features, and fruit/seed morphology. In Malvaceae, we resolved uncertainties in the early Malvoideae lineages, and we describe a new tribe, Pentaplareae tr. nov., which clarifies the taxonomic placement of a previously uncertain genus. Additionally, we propose the recognition of a new subfamily, Matisioideae subfam. nov., elevated from its former status as a tribe, and positioned as the sister group to Malvoideae. This study highlights how taxonomic frameworks can be refined even in the face of conflicting phylogenomic data, demonstrating the importance of integrating molecular and morphological evidence in revising classifications.