臭根子草 chou gen zi cao

Perennial, tufted. Culms erect or decumbent at base, fairly robust, up to 130 cm tall, many-noded, nodes glabrous or appressed bearded. Leaf sheaths glabrous; leaf blades linear, 10–40 × 0.2–1 cm, hairy with tubercle-based hairs on both surfaces or abaxial surface glabrous, apex finely acuminate; ligule 0.5–1.5 mm. Inflorescence 9–20 cm, composed of many racemes borne in loose whorls along an elongate central axis, axis usually longer than lowest raceme, sometimes paniculate with branchedpeduncles; racemes 2–5 cm, often purplish, not obviously hairy; rachis internodes and pedicels thinly ciliate, shortly bearded at apex. Sessile spikelet 3–4 mm; lower glume narrowly oblong-lanceolate, herbaceous or cartilaginous and glossy, 5–7-veined, back slightly concave, glabrous or pubescent below middle, sometimes with a pit, margins keeled and scabrid near apex; awn of upper lemma 1–2.5 cm. Pedicelled spikelet barren or rarely staminate, narrower than sessile spikelet, sometimes pitted. Fl. and fr. Jul–Oct. 2n = 40, 60, 80.

Exposed slopes, waste ground; 400–1600 m. Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hubei, Hunan, Shaanxi, Sichuan, Taiwan, Xinjiang, Yunnan [Bhutan, India, Indonesia, Japan, Malaysia, Nepal, New Guinea, Pakistan, Thailand, Vietnam; Africa, SW Asia, Australia; introduced in America].

Bothriochloa bladhii hybridizes easily and frequently with some other species of Bothriochloa, and also with Capillipedium parviflorum and Dichanthium annulatum, blurring the boundaries between these genera and leading to a host of intermediates. New, apomictic races have arisen from among these products of introgression, causing much taxonomic difficulty. The name B. glabra has been applied to hybrids between B. bladhii and C. parviflorum.

Bothriochloa bladhii is most practicably treated in a broad sense to include all forms with an elongate inflorescence axis. Additionally, the habit is usually not stoloniferous, and the racemes are less obviously hairy than in B. ischaemum and B. pertusa.