[Botany • 2026] Ophiorrhiza bibracteata (Rubiaceae) • A New Species from Guangxi, China

Ophiorrhiza bibracteata Y.Nong & G.Y.Wei, 

in Nong, G.-Y. Wei, H.-Y. Wei, Long, Liu, Feng et Qin, 2026.

金钟山蛇根草  ||  DOI: doi.org/10.3897/phytokeys.275.189773

Abstract

Ophiorrhiza bibracteata (Rubiaceae), a new species from northwest Guangxi, China, is described and illustrated. It can be distinguished from its allies O. mitchelloides, O. nanlingensis and O. grandibracteolata by the shape and size of the bracts (ovate, 8–11 mm long) and the shape and size of the calyx lobes (triangular, 0.8–1.0 mm long, glabrous, with glands between the lobes). According to the IUCN Red List Categories and Criteria, the new species is assessed as Data Deficient (DD) until more information becomes available.

Key words: Morphology, new species, Ophiorrhiza, taxonomy

Ophiorrhiza bibracteata Y.Nong & G.Y.Wei.
A, B. Habit; C, D. Flowering plant; E. Brevistylous flower (front view); F. Flower (lateral view); G. Dissected brevistylous flower; H. Dissected longistylous flower; I. Ovary, calyx, style and stigma of longistylous (left) and brevistylous (right) flower; J. Ovary, calyx, style and stigma of brevistylous flower; K. Stipule; L. Bracts and flower bud; M. Leaf, adaxial surface; N. Leaf, abaxial surface; O. Fruiting plant; P. Capsules and bracts (images captured with a Nikon D850 camera).

Ophiorrhiza bibracteata Y.Nong & G.Y.Wei, sp. nov. 

Diagnosis. Ophiorrhiza bibracteata is similar to O. mitchelloides (Masam.) H.S.Lo, but differs in the following characters: the number of secondary veins (5–7 pairs in O. bibracteata vs. 3–5 pairs), the shape and size of the bracts (ovate, 8–11 mm long vs. linear, 4–8 mm long), the shape and size of the calyx lobes (triangular, 0.8–1.0 mm long, glabrous, with glands between the lobes vs. linear, ca 1.4 mm long, glabrescent or ciliate, without glands) and the nature of the flowers (distylous vs. monostylous).

Etymology. The specific epithet is derived from the Latin, bibracteata, meaning “two bracts” and referring to the two persistent ovate bracts of the new species.

Chinese name. 金钟山蛇根草 (jīn zhōng shān shé gēn căo).

 You Nong, Gui-Yuan Wei, Hai-Yong Wei, Lie Long, Zhi-Rong Liu, Bin Feng and Ting Qin. 2026. Ophiorrhiza bibracteata (Rubiaceae), A New Species from Guangxi, China.  PhytoKeys. 275: 151-161. DOI: doi.org/10.3897/phytokeys.275.189773 [29 May 2026]