Wednesday, November 24, 2021

[Botany • 2021] Biancaea scabrida (Fabaceae: Caesalpinioideae) • A New Species of the Caesalpinia group from Peninsular Malaysia


Biancaea scabrida L.M.Choo  

in Choo, 2021. 
Drawn by Loh Xiang Yun  
 
Abstract
The new species Biancaea scabrida, currently only known from Peninsular Malaysia, is described and illustrated. The new species most resembles B. parviflora and B. oppositifolia in its inflorescence, but can be distinguished from both species by its sepals which have short stiff scabrid hairs, and its pistil which has stiff and hispid hairs. It also has alternately arranged leaves and inflorescence branches, a lack of a persistent suborbicular stipule, few pinnae per rachis (2–6 pairs) and relatively fewer leaflets per pinna ((3–)5–9 pairs). A provisional IUCN conservation assessment and a taxonomic key to Biancaea is also provided here.

Keywords: Caesalpinia, Caesalpinioideae, Kelantan, limestone hill, Perak, taxonomy 

Photo of the holotype of  Biancaea scabrida.

 Illustration of Biancaea scabrida L.M.Choo. 
 A: inflorescence; B: flower; C: inner surface of receptacle and sepals; D: outer surface of receptacle and sepals; E: inner surface of lateral petal; F: inner surface of standard petal; G: inner surface of basal petal; H: pistil; I: closeup of stigma; J: stamen; K: seed; L: pod.
Drawn by Loh Xiang Yun from the holotype Loh FRI 19256, SING[SING0256191] for A, and from Turner 94-91 [SINU] for B-L.

Biancaea scabrida L.M.Choo, sp. nov. 
TYPE:—Peninsular Malaysia, Kelantan, Gua Musang, 23 Feb 1972, Loh Hoy Shing FRI 19256 (holotype SING! [SING0256191] (fl); isotype KEP [KEP136564] (fl); isotype L! [L1976278] (fl)). 

Diagnosis:—This species is the most similar to Biancaea parviflora and Biancaea oppositifolia in its small, compact flowers, borne on a long inflorescence, which are very much smaller than other species in the genus. However, it differs from both species by the sepals which have short, stiff scabrid hairs, and by the stiff and hispid hairs on the pistil, which is especially visible at the style where the hairs are sticking out, as compared to B. parviflora and B. oppositifolia where the hairs are soft and adpressed. It can be distinguished from B. parviflora by its larger and ovate-elliptic leaflets, fewer pinnae per rachis (2–6 pairs) and fewer leaflets per pinna ((3–)5–9 pairs). It can also be distinguished from B. oppositifolia by its alternately arranged leaves and inflorescence branches, and also by the lack of large, persistent and suborbicular stipules.

Distribution:—Biancaea scabrida is known from two locations in Peninsular Malaysia, Gua Musang in the State of Kelantan and Tasik Temenggor in Perak. 

Habitat:—Limestone hill. 

Etymology:—The specific epithet is derived from the Latin word scaber, which means rough to the touch because of numerous minute projections. This refers to the hairs on the sepals which are short, stiff and scabrid on both surfaces.


Le Min Choo. 2021. Biancaea scabrida, A New Species of the Caesalpinia group (Fabaceae) from Peninsular Malaysia. Phytotaxa. 525(4); 251-257. DOI: 10.11646/phytotaxa.525.4.1