Description from Flora of China
Adatoda Adanson; Adhatoda Miller; Calophanoides Ridley; Ecbolium Kuntze (1891), not Kurz (1871); Gendarussa Nees; Mananthes Bremekamp; Rhaphidospora Nees; Rostellaria Nees (1832), not C. F. Gaertner (1807); Rostellularia Reichenbach.
Herbs, subshrubs, or shrubs, cystoliths present. Leaves sessile or petiolate; leaf blade margin usually entire but sometimes sinuate or slightly serrate. Inflorescences dichasia (sometimes reduced to a single flower) in leaf axils or axillary or terminal spikes, racemes, or thyrses, sometimes branched and becoming panicles; bracts variable in shape, sometimes prominent and/or brightly colored; bracteoles 2, similar to or smaller than bracts. Calyx deeply 4- or 5-lobed; lobes equal or subequal. Corolla tubular or funnel-shaped; limb strongly 2-lipped; lower lip 3-lobed; upper lip entire to 2-lobed, internally rugulate (i.e., with a stylar furrow); lobes ascending cochlear in bud. Stamens 2; anthers 2-thecous; thecae equally or unequally inserted, parallel to perpendicular, one or both spurred at base or sometimes lacking basal appendages; staminodes absent. Ovary with 2 ovules per locule; stigma slightly 2-lobed. Capsule with a sterile basal stalk and a fertile head (i.e., ± clavate), 2-4-seeded; retinacula present. Seeds compressed [to spheric].
Justicia betonica Linnaeus, J. brandegeeana Wasshausen & L. B. Smith, and J. carnea Lindley are only cultivated in China so are not treated here.
Wuacanthus Y.F. Deng, N.H. Xia & H. Peng, gen. nov. (http://dx.doi.org/10.1016/j.pld.2016.11.010) – Type: Wuacanthus microdontus (W.W.Sm.) Y.F. Deng, N.H. Xia & H. Peng, Pl. Diversity (http://dx.doi.org/10.1016/j.pld.2016.11.010).
Wuacanthus microdontus (W.W.Sm.) Y.F. Deng, N.H. Xia & H. Peng, comb. nov.≡Justicia microdonta W.W. Sm. in Not. Bot. Gard. Edinb. 10: 183. 1918. ≡
Mananthes microdonta (W.W. Sm.) C.Y. Wu & C.C. Hu in C. C. Hu, Fl. Reipubl. Popularis Sin. 70: 296. 2002. – Type: CHINA. Yunnan: mountains of the Chungtien Plateau [27°30'N], July 1914, G. Forrest 12822 (Lectotype E! here designated; isolectotype K!).Fig. 4.
About 700 species: tropical and temperate regions worldwide; 43 species (26 endemic, three introduced) in China.
(Authors: Hu Jiaqi (胡嘉琪 Hu Chia-chi), Deng Yunfei (邓云飞); Thomas F. Daniel)