Friday, December 16, 2022

[Botany • 2022] Microchirita minor (Gesneriaceae: Didymocarpoideae) • A New Species from north-western Vietnam


Microchirita minor Z.B.Xin, T.V.Do & F.Wen,  

in Xin, Li, Maciejewski, Fu, Do & Wen, 2022.

Abstract
Microchirita minor (Gesneriaceae), a new species from the limestone area in Son La Province, north-western Vietnam, is described here. The new species resembles M. hamosa, but it differs by the combination of corolla tube shape, stamens number and the length of pistil. Detailed morphological description, together with photographic plates, information on phenology, distribution, ecology and preliminary conservation status of the new species are presented.

Keywords: Didymocarpoideae, Flora of Vietnam, karst limestone, Microchirita

Microchirita minor sp. nov.
 A habit B flower C opened corolla with stamens and staminodes; D abaxial surface of calyx lobes E pistil and calyx.
Drawn by Rui-Feng Li.

A–H Microchirita minor sp. nov. I–J M. hamosa
A habitat B plants with flowers C abaxial surface of leaf blade D adaxial surface of leaf blades E calyx lobes (adaxial surface above, abaxial surface below) F lateral view of the flower G pistil and calyx H opened corolla with stamens and staminodes I habitat J plant with flowers.
(Photos C–H from type material).

 Microchirita minor Z.B.Xin, T.V.Do & F.Wen, sp. nov.
 
Diagnosis: The new species is morphologically similar to Microchirita hamosa, but it differs from the latter in its corolla tube 5–6 mm long, with four yellow patches, each one originating at the base of each filament and reaching the throat, the throat-base diameter ratio of the corolla tube 1–1.2 (vs. corolla tube 8–15 mm long, with one yellow patch ventrally, the throat-base diameter ratio of the corolla tube 2–3); stamens 4, 2–2.5 mm long, ca. 0.3 mm in diameter (vs. stamens 2, ca. 1.5 mm long, ca. 0.1 mm in diameter); pistil 6–8 mm long (vs. ca. 16 mm long); ovary 2–3 mm long (vs. ca. 14 mm long).
 
Etymology: Latin minor, smaller, alluding to size of plants and flowers.
 
Distribution and habitat: The new species is currently only known from one population within Xuan Nha Nature Reserve, Moc Chau District, Son La Province, north-western Vietnam. The new species grows in moist crevices of the limestone cliff and mouth of limestone caves in a subtropical evergreen seasonal rainforest, at elevations of 530–545 m.



  Zi-Bing Xin, Rui-Feng Li, Stephen Maciejewski, Long-Fei Fu, Truong Van Do and Fang Wen. 2022. Microchirita minor (Gesneriaceae), A New Species from north-western Vietnam. PhytoKeys. 215: 65-71. DOI: 10.3897/phytokeys.215.90859