Pentagonia santanderensis (Rubiaceae, Dialypetalantheae) is described and illustrated from the department of Santander, occurring in the municipalities of Cimitarra, La Belleza, and Landázuri in fragmented forests and primary forest edges associated with water sources. We compare this new taxon with morphologically similar species; the size of its leaves, the magenta coloration of the strongly pleated leaf bases, and the color, indumentum, and size of the corolla, as well as the fruits, are diagnostic characters. This new species increases the number of Pentagonia species recorded in Colombia to 23. Based on the IUCN criteria, P. santanderensis is assessed as Endangered (EN B2a(ii)b(iii)) due to its restricted distribution and continuing decline in habitat quality.
Impatiens tanahkaroensis is described here as a new species known from the mountainous regions north of the Lake Toba area, northern Sumatra, Indonesia. It is a rheophytic species growing on a small stream, which is potentially threatened by flash floods. A detailed description, discussion, and living photographs are given.
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.
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.
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).
