Description from Flora of China
Cryptophragmium Nees; Sarcanthera Rafinesque.
Herbs, perennial [or shrubs], with cystoliths. Leaves cauline or subradical, opposite; leaf blade margin usually entire. Inflorescences axillary or terminal, spikes, racemes, or panicles, often secund; bracts and bracteoles shorter than calyx. Calyx 5-lobed nearly to base; lobes subequal. Corolla tube longer than limb, basal portion narrowly cylindric, ± expanded distally into a throat; limb 2-lipped, lower lip 3-lobed, upper lip emarginate to 2-lobed; lobes ascending cochlear in bud. Stamens 2, included in or slightly exserted from corolla tube; anther thecae 2, equal or subequal in size, parallel, one or both mucronate at base; staminodes absent. Ovary with 3 to many ovules per locule; stigma 2-lobed, lobes compressed. Capsule without a stipe, linear, 4-angled, many seeded; retinacula present. Seeds compressed, covered with hygroscopic trichomes.
About 30 species: tropical Asia; three species (two endemic) in China.
(Authors: Hu Jiaqi (胡嘉琪 Hu Chia-chi), Deng Yunfei (邓云飞); Thomas F. Daniel)