67. Origanum Linnaeus, Sp. Pl. 2: 588. 1753.
牛至属 niu zhi shu
Subshrubs or perennial herbs, gynodioecious, aromatic. Leaves ovate to oblong-ovate, entire to remotely dentate. Spikes cylindric to oblong, sometimes elongated in fruit, many flowered, overlapping with small bracts, in corymbose panicles; bracts and bracteoles green and purple-red, oblong-obovate to lanceolate. Calyx campanulate, throat villous annulate, ca. 13-veined; teeth 5, subtriangular, subequal, apex acute to obtuse. Corolla white or rose to purple, campanulate, tube exserted, limb 2-lipped; upper lip straight, emarginate; lower lip spreading, 3-lobed, middle lobe larger than lateral lobes. Stamens 4, shorter to slightly longer than upper lip in bisexual flowers, included in pistillate flowers; anthers ovoid, cells 2, separated by triangular cuneate connectives; filaments glabrous. Style exserted, apex unequally 2-cleft. Nutlets ovoid, slightly ribbed, dry, glabrous.
About 15-20 species: primarily in SW and C Asia, one in China.