A synopsis of Rhinacanthus (Acanthaceae) in Angola and Namibia

Abstract

Summary. The three species of the genus Rhinacanthus Nees occurring in Angola and Namibia are documented, including a full description of the new species R. angolensis I. Darbysh. and an expanded description of the scarce species R. kaokoensis K. Balkwill & S. D. Will. A key to their identification is provided, together with notes on their conservation status and species affinities.

Sixty-seven species newly recorded for the flora of Angola: recent findings from vegetation surveys and herbarium collections

“…The checklist of Figueiredo and Smith (2008) was used as the baseline for assessing Angolan species records. Species missing there but subsequently reported in later publications (Swanepoel 2009;Bergh and Nordenstam 2010;De Sousa et al 2010;Catarino et al 2013;Abreu et al 2014;Hind and Goyder 2014;Paton 2014;Cheek et al 2015;Darbyshire 2015;Abrahamczyk et al 2016;Darbyshire et al 2018;Harris and Wortley 2018a, 2018b, 2018cDarbyshire and Goyder 2019;Swanepoel 2019;Tripp and Darbyshire 2020;Lautenschläger et al 2020b;Darbyshire et al 2021;Smith and Lautenschläger 2021;Swanepoel et al 2021, Figueiredo andSmith 2022) were excluded.…”

A synopsis of Ruellia (Acanthaceae) in Angola, including two species new to science

“…Other endemic Acanthaceae of this region include Rhinacanthus kaokoanus K.Balkwill & S.D.Will. (Balkwill, 1995;Darbyshire et al, 2018) and Suffruticose perennial herbs, with few to numerous erect stems 10-30 cm tall arising from a short woody base (rhizome) with thick, fleshy roots; whole plant drying dark brown or green-brown; stems densely pilose to somewhat villose with patent long multicellular eglandular hairs 1.7-3.3 mm long, these (pinkish-)brown, lustrous, straight or the longest hairs becoming somewhat crisped, also with two opposite lines of inconspicuous short, ± retrorse eglandular hairs, distal portions of stems with interspersed minutely gland-tipped hairs, these shorter than or subequal to the long eglandular hairs. Leaves petiolate, petiole 3-14 mm long, pilose; blade ovate to ovate-elliptic or narrowly so, 4.3-8 × 1.9-5 cm (l : w ratio 1.4-3 : 1), base rounded, obtuse or cuneate, margins entire or very shallowly crenate-serrate, apex acute, surfaces eglandular-pilose, densely so when young, hairs can be most dense on veins beneath, sometimes with few interspersed glandular hairs; cystoliths numerous; lateral veins 6-7 per side.…”

Rhinacanthus spiciformis, a new species of Acanthaceae from northern Vietnam

“…The genus Rhinacanthus Nees (Acanthaceae) comprises approximately 30 species distributed mainly in tropical regions of Africa and Asia (Mabberley , Darbyshire et al ). Traditionally, it was placed in the subtribe Justicinae (Lindau , Bremekamp , Hansen , Hu ).…”

“…Recent molecular data indicate that it might belong in the Diclipterinae clade of the ‘Justicioid’ lineage (McDade et al , Kiel et al , Darbyshire et al ). Rhinacanthus is characterized by the combination of a long, narrowly cylindrical corolla tube usually exceeding the length of the bilabiate limb, two stamens, bithecous anthers, thecae offset ± oblique and lacking a basal appendage, and a long‐stipitate and shortly beaked 4‐seeded capsule (Darbyshire and Harris , Darbyshire et al ).…”

“…Rhinacanthus nasutus is distributed in tropical Asia and extending to the Mascarenes and Madagascar where it is likely introduced (Clarke , Bremekamp , Cramer , Kress et al , Hu et al ). Recent studies indicate that the records in tropical Africa (Clarke , , Heine , , Ake Assi ) should be excluded (Balkwill , Darbyshire and Harris , Darbyshire , Darbyshire et al ). Rhinacanthus calcaratus is recorded from India, Bhutan, Myanmar, Thailand and Vietnam (Clarke , Lindau , Benoist , Wood , Kress et al , Kantachot ).…”