Description from Flora of China
Herbs perennial, terrestrial, not aromatic, with ± fleshy rhizomes. Stems usually simple, often long, terete, sometimes spirally contorted, leafy; secondary branches (if present) breaking through leaf sheaths. Leaves spirally arranged, simple, those toward base of stem usually bladeless; leaf sheath tubular, closed; ligule present; petiole short; leaf blade narrowly to broadly elliptic, rolled longitudinally in bud, glabrous or hairy, margin entire. Inflorescence a conelike spike, terminal on leafy shoots or on separate, short, leafless shoots arising from rhizomes; bracts imbricate, with linear, nectariferous callus below apex, 1- or 2-flowered; bracteoles tubular or folded. Flowers bisexual, epigynous, zygomorphic. Calyx tubular, 2- or 3-lobed or -toothed. Corolla proximally tubular, distally 3-lobed; lobes unequal, imbricate in bud. Staminodes 5, united into a labellum equaling or much longer than corolla, often ± 3-lobed with crisped margin, never deeply lobed. Fertile stamen 1; filament broad; anther borne below apex of filament or at apex with a connective crest, introrse, dehiscing by longitudinal slits. Ovary inferior, 2- or 3-loculed; ovules many per locule; placentation axile. Developed style 1, filiform, usually enclosed between anther locules; stigma with or without abaxial appendage. Stylodes 2, reduced to septal, hollow nectaries at apex of ovary, or absent. Fruit a capsule, 2- or 3-valved and dehiscing loculicidally, or indehiscent and breaking up irregularly, apex with persistent calyx. Seeds numerous, black, arillate.
Tsai Hsi-tao & Tong Shao-quan. 1981. Zingiberaceae subfam. Costoideae. In: Wu Te-lin, ed., Fl. Reipubl. Popularis Sin. 16(2): 148--152.
Four genera and ca. 120 species: pantropical with center of diversity in America; one genus and five species (two endemic) in China.
(Authors: Wu Delin (吴德邻 Wu Te-lin); Kai Larsen)