Monday, April 4, 2022

[Botany • 2022] Oreocharis phuongii (Gesneriaceae) • A New Species from central Vietnam


 Oreocharis phuongii T.V.Do, 

in Le, Nguyen, ... et Do, 2022. 

Abstract
Oreocharis phuongii, a new species of Gesneriaceae from central Vietnam, is described and illustrated here. The new species is most similar to O. longifolia by sharing peduncles up to 22 cm long, bracts 2, zygomorphic, yellow flowers with tubular corolla, stamens 4 with two pairs of coherent anthers and capsules up to 6 cm long. It mainly differs from the latter by the combination of some morphological characters of leaves (shape, base, apex and margin), size of calyx lobes, indumentum of corolla tube and inner surface of three lower corolla lobes. Detailed morphological description together with colour illustration, information on phenology, distribution, ecology, preliminarily conservation status of the new species and comparison with its similar species are also presented.

Keywords: Annamite Range, Didymocarpoideae, endemic to Vietnam, Flora of Vietnam, limestone flora, new taxon

Oreocharis phuongii sp. nov. (A–J) A habitat B habit showing cymose inflorescence C adaxial leaf surface D abaxial leaf surface E–F structure of floral parts (two pairs of anther and filament indicated by a white arrow; shape of pistil indicated by a green arrow) G frontal view of opened flower showing backwards incurved upper lobes, glabrous inner surface of three lower lobes and a bilobed matured stigma longer than stamens (indicated by a blue arrow) H lateral view of opened flower I close-up of opened flower (in frontal view) J close-up of 2-paired stamens;
O. longifolia (K–M) K habit L frontal view of opened flower showing brown to brownish-yellow inner surface of three lower lobes with dark-purple striations M lateral view of an opened flower.
 A–J photos by Do Van Truong K–M photos by Nicholas Turland.


 Oreocharis phuongii T.V.Do, sp. nov.
 
Diagnosis: The new species is morphologically similar to O. longifolia W.H.Chen in having peduncles up to 22 cm long, bracts 2, zygomorphic, yellow flowers with tubular corolla, stamens 4 and capsules up to 6 cm long; but it differs from the latter in its elliptic to ovate lamina (vs. narrowly elliptic to oblanceolate), cuneate to nearly rounded leaf base (vs. attenuate), obtuse to almost rounded leaf apex (vs. acute), crenulate margin (vs. serrulate), 3–4.5 × 1.5–1.8 mm calyx lobe size (vs. 5–7 × 2–3 mm), glabrous inner surface of corolla tube (vs. sparsely glandular puberulent with dark-purple striations) and exclusively yellow inner surface of three lower lobes without dots and striations (vs. brown to brownish-yellow with purple dots and striations).

Etymology: The specific epithet honours Prof. Dr. Vu Xuan Phuong who has contributed significantly to our understanding of Gesneriaceae in Vietnam.


 Khuong Duy Le, Thanh Trung Nguyen, Phuong Thanh Nguyen, Thao Thi Hoang, Fang Wen and Truong Van Do. 2022. Oreocharis phuongii (Gesneriaceae), A New Species from central Vietnam. PhytoKeys. 193: 43-53.  DOI: 10.3897/phytokeys.193.77083