Two new species of Keetia are described from recent botanical collections for conservation management made in surviving submontane forest areas of the sandstone plateau areas of the Republic of Guinea. Keetia kounounkan Cheek & Simbiano is a shrub of the Kounounkan Plateau towards the border of Sierra Leone, so far with a single location in gallery forest. K. tinka Cheek & Simbiano is an evergreen rainforest climber of the main part of the Fouta Djalon Highlands with two locations both in degraded forest. Both species are described, illustrated and provisionally assessed for their conservation status, the first as Critically Endangered, the second as Endangered.

A taxonomic revision of Lasiacis (Griseb.) Hitchc. 47 years since the last contribution (Davidse 1978) is proposed here. Historical and recent collections across 35 herbaria have been examined. Typifications are confirmed or emended, and 8 lectotypes are here designated (see Appendix III). Vernacular nomenclature and economic and therapeutic uses are updated based on bibliographic data or on information from herbarium specimens. For each taxon examined, an iconograph supporting the main diagnostic characters is proposed. Taxa previously described as varieties, such as L. divaricata var. austroamericana, L. rugelii var. pohlii, and L. ruscifolia var. velutina are elevated to the rank of species, and L. acuminata Swallen has been resurrected as a valid species, recognizing a total of 22 taxa, 18 species and 4 varieties.

Plagiosiphon intermedium Burgt, Ngansop & Tchiengué, Leguminosae–Detarioideae, is described and illustrated. It is a tree, to 34 m high, with a stem to 66 cm diameter. The leaves have (2 –)3–4(– 5) pairs of opposite leaflets, with the lowest pair often sub-opposite. The flowers are unknown. The fruit is a pod, brown, the valves more or less obovate in outline, 7–9.5 × 3.5–4.5 cm, without visible veins outside, short dense hairy outside. Plagiosiphon intermedium occurs in primary rain forest, at 760–870 m elevation. The tree species is endemic to the Ngovayang Massif in the South Region of Cameroon. Three herbarium collections have been made, in an extent of occurrence of only 0.51 km2. Plagiosiphon intermedium is provisionally assessed as Endangered B1(iii,v)+B2(iii,v).

The complex nomenclature of the Cuban endemic palm Copernicia macroglossa Schaedtler is revisited. The research involved looking into six validly published names and resulted in a revision of the lectotypification of C. ×macroglossa H.Wendl. ex Becc. (accepted name C. ×escarzana León) and a reevaluation of previous typification accounts for C. ×escarzana León, C. ×burretiana León, and C. torreana León.

The recently recognised Quadrispina clade within Barleria sect. Prionitis Nees (Acanthaceae) represents a taxonomically challenging group endemic to the Horn of Africa biodiversity hotspot. This study presents a comprehensive taxonomic revision of the complex, driven by morphological assessment and morphometric analyses. We recognise seven species in the complex in total, including four new species to science that had previously been included within B. quadrispina, namely B. filtuensis, B. mudugensis, B. puberulifolia and B. sebsebei. In addition, we recognise four subspecies within B. quadrispina, namely subsp. quadrispina, subsp. glaucobracteata, subsp. waggana and the newly described subsp. kenyana. Conservation assessments based on IUCN Red List categories and criteria indicate that B. filtuensis, B. mudugensis, B. puberulifolia, B. sebsebei and B. quadrispina subsp. glaucobraceata are range-restricted and potentially threatened by habitat degradation, hence they are preliminarily assessed as threatened under criterion B, whilst B. quadrispina subsp. kenyana remains Data Deficient.

This issue is dedicated to the 120th anniversary of Webbia’s founding. It is a fitting tribute to a journal that has been and continues to be a point of reference in the history of Plant Taxonomy and Geography in Italy and abroad. The contributions presented here reflect the journal’s international vision, focused on enhancing plant biodiversity in increasingly threatened parts of the World. Thanks go to all the authors present here who responded to my appeal, and for whom I am deeply grateful.

Currently 39 species of Ardisia are recognised from continental Africa, of which three (A. sadebeckiana Gilg, A. schlechteri Gilg, and A. ebo Cheek, each endemic to Cameroon and known from a single collection) are herbaceous, with creeping, horizontal, rooting herbaceous stems, the stem apex more or less ascending to up to c. 10 cm tall above the ground (decumbent). These species lack the distinctive plagiotropic (perpendicular and horizontal) aerial reproductive stems seen in most woody Ardisia species of Africa (instead sporadically producing rooting ascending stems from the horizontal stem) and have distichous leaves (not spiralled as in most species in Africa). Accordingly, they are proposed as a separate subgenus Kamardisia. Study of herbarium material revealed that six additional species exist which are described and illustrated in this paper, together with preliminary conservation assessments. These are: A. hansii (South Region, Cameroon and Belinga, Gabon), A. massaha (Belinga, Gabon), A. chaillu, A. minuta, A. waka (all Chaillu Massif, Gabon), A. ngounie (Ogooué-Maritime, Gabon). We provide a key to the identification of the nine herbaceous species, provide preliminary conservation assessments for each, and notes on shared characteristics of the African herbaceous species including the taxonomic value of leaf microcharacters (oil glands and trichomes). We also make a preliminary report on the possibility of bacterial colonisation of marginal leaf pores in some of these herbaceous species. All of the species are range restricted, the most wide-ranging with only three sites. All but one species is threatened, and almost all of those are Critically Endangered (provisional assessments). The two first published species have not been seen for more than 125 years, despite being in easily accessible, well-botanised locations, and are both feared extinct. We discuss actions to attempt to refind these species and safeguard the remainder.

To investigate the evolutionary relationships among 23 species in the Cotteinae we generated a DNA sequence-derived phylogeny utilizing three plastid (rps16-trnK spacer, rps16 intron, rpl32-trnL spacer) regions and the nuclear ribosomal internal transcribed spacer (ITS) region. The Bayesian tree provides strong support for the monophyly of the Cotteinae and its four genera, in order of divergence: Cottea, the Kaokochloa + Schmidtia clade, and the Enneapogon clade. Since the Eragrostideae clearly evolved from African ancestors and Kaokochloa, Schmidtia, and Enneapogon all share species from Africa, we hypothesize the ancestral area of Cotteinae to be Africa. Within Enneapogon we recovered four major clades, the first two splits with species primarily from Africa and the third split containing a basal species from Africa/Asia/Europe sister to all species from Australia. The ancestral area of Enneapogon is Africa and based on our current sample the 13 species from Australia appear to be derived from a single dispersal event from an ancestor shared with E. persicus.

Recently it became clear that at least some of the varieties and subspecies that are currently recognised in Bakerella Tiegh. (Loranthaceae) from Madagascar are better placed as species. In several cases these taxa were originally already described as species but not yet in Bakerella, so new combinations are needed. The first four new combinations are published here.

In this study, we provide a comprehensive and updated overview of the biogeographic history of several Brazilian phytogeographic domains: the Amazon Rainforest, Brazilian Atlantic Forest, Caatinga, Cerrado, Pampa, and Pantanal. We also outline the main hypotheses that were proposed to explain the distribution patterns and endemism of taxa within these domains. The tropical forests, specifically the Amazon Rainforest and the Brazilian Atlantic Forest, were likely continuous during the Eocene optimum. However, global cooling and increased aridity in the late Eocene and part of the Oligocene led to the fragmentation of these extensive tropical forests. This fragmentation resulted in the creation of the dry diagonal, which includes the Cerrado, Caatinga, Pantanal, and Chaco regions. The dry diagonal served as a geographic barrier, promoting the formation of the Brazilian Atlantic Forest to the East and the Amazon Rainforest to the West. Despite this barrier, forest corridors likely existed between these domains, playing a crucial role in the segregation of the Caatinga from the Cerrado. The Caatinga is the most recent of these domains, having formed in the early to mid-Holocene. The lineages characteristic of the Cerrado likely diversified between the Miocene and early Pliocene.