Hemiboea siccinvolucris (Gesneriaceae), a new species from northeastern Guangxi, China

A new species of Gesneriaceae, Hemiboea siccinvolucris B. Pan & Y. B. Lu, sp. nov., from Guangxi, China, is described. This species is morphologically similar to H. cavaleriei, H. subcapitata, and H. liana but can be distinguished by its densely pubescent adaxial surface and sparsely pubescent abaxial surface (vs. adaxially glabrous to sparsely pubescent and abaxially glabrous in H. cavaleriei; adaxially nearly glabrous to pubescent and abaxially glabrous to pubescent in H. subcapitata; glabrous on both surfaces in H. liana) and by its green abaxial surface (vs. pale green or purplish in H. cavaleriei and H. subcapitata; lilac in H. liana).

The terminal cyme has only 1–3 flowers (vs. pseudoterminal or axillary cymes with three or more flowers in H. cavaleriei and H. subcapitata; terminal, usually 1 - flowered, occasionally 2 - flowered in H. liana). The spherical involucre dries early before anthesis (vs. spherical, with no records of early involucre desiccation in H. cavaleriei and H. subcapitata; trigonous, with no records of early involucre desiccation in H. liana); the stigma is reniform (vs. obtuse in H. cavaleriei and H. subcapitata; shallowly bilobed in H. liana).

Phylogenetic analyses based on both ITS sequences and chloroplast genome data show that all sampled individuals of this taxon form a well-supported monophyletic group, supporting its recognition as a new species. Detailed morphological descriptions, line drawings, comparative diagnostic characters, and molecular phylogenetic analyses are provided.