[Botany • 2026] Didymocarpus xuanlienensis (Gesneriaceae) • A New Species from Vietnam

 

Didymocarpus xuanlienensis T.S.Hoang, W.G.Wang & H.C.Xi,  

in Tran, Hoang, Wang, Lang et  Xi, 2026. 

Song quả Xuân Liên  ||  DOI: doi.org/10.3897/phytokeys.275.185766

 

Abstract

Didymocarpus xuanlienensis, a new species from Vietnam, is described and illustrated here. It is morphologically similar to D. brevipedunculatus and D. purpureobracteatus in terms of corolla size and color but differs from D. brevipedunculatus in leaf blade shape, bract shape, indumentum, and calyx shape and differs from D. purpureobracteatus in peduncle indumentum, bract shape, and calyx shape. A detailed morphological description of the new species and a key to all Didymocarpus species in Vietnam are provided.

Key words: Didymocarpus, new taxon, taxonomy, Vietnam

Didymocarpus xuanlienensis T.S.Hoang, W.G.Wang & H.C.Xi, sp. nov.
A. Habitat; B. Flowering plant; C. Leaves, adaxial and abaxial views; D. Inflorescences; E. Part of inflorescence, showing peduncle, pedicel and bracts; F. Bracts; G. Calyx and disc; H. Flowers; I. Dissected corolla, showing stamens and pistil (Photos by Son Thanh Hoang).

Didymocarpus xuanlienensis T.S.Hoang, W.G.Wang & H.C.Xi, sp. nov.

 

Diagnosis. The new species differs from the most similar species, Didymocarpus brevipedunculatus Y.H.Tan & Bin Yang, (2019: 191), in leaf blade elliptic to oblong, base cuneate (vs. ovate, base extremely obliquely cordate); bracts broadly ovate, glabrous (vs. orbicular to ovate, sparsely villous); calyx broadly campanulate, lobes triangular (vs. campanulate, lobes ovate to semiorbicular). D. xuanlienensis is also similar to D. purpureobracteatus W.W.Smith, (1912: 153) but differs from it in peduncle glandular-pubescent (vs. glabrous); bracts free (vs. often connate at base); calyx actinomorphic, broadly campanulate, lobes triangular (vs. slightly zygomorphic, tubular campanulate, lobes semiorbicular). Moreover, the new species differs from D. brevipedunculatus and D. purpureobracteatus in distribution, elevation, and flowering time. A detailed morphological and ecological comparison of these three species is presented in Table 1.

Van Thi Thuy Tran, Son Thanh Hoang, Wen-Guang Wang, Xiao-An Lang and Hou-Cheng Xi. 2026. Didymocarpus xuanlienensis, A New Species of Didymocarpus (Gesneriaceae) from Vietnam. PhytoKeys. 275: 73-79. DOI: doi.org/10.3897/phytokeys.275.185766 [21 May 2026]