91. Acrocephalus Bentham, Edward's Bot. Reg. 15: t. 1282. 1829.
尖头花属 jian tou hua shu
Herbs annual, slightly rigid. Leaves short petiolate, dentate. Verticillasters in terminal or rarely axillary, globose or cylindric capitula; floral leaves 2 or 4, bright colored; bracts numerous, overlapping, conspicuous. Flowers pedicellate. Calyx ovoid in flower, tubular, saccate at base in fruit, slightly constricted at glabrous throat, limb 2-lipped, upper lip entire or dentate; lower lip entire, apex emarginate or 4-toothed. Corolla bluish or purplish, rarely white, throat dilated, limb 2-lipped, upper lip short 4-lobed; lower lip entire, slightly longer than upper, sometimes lobes subequal. Stamens 4, declinate; filaments free, edentate, inserted on throat; anthers ovoid. Style apex equally 2-cleft. Nutlets ovoid or oblong, smooth.
About five or six species: Asia, one species in China.
African plants formerly included in this genus are now placed in Haumaniastrum.
