119. Danthonia Candolle in Lamarck & Candolle in Lamarck & Candolle, Fl. Franç., ed. 3. 3: 32. 1805.
扁芒草属 bian mang cao shu
Authors: Zhen-lan Wu & Sylvia M. Phillips
Sieglingia Bernhardi, nom. rej.
Perennial. Culms tufted, erect, cleistogenes often present in culm sheaths. Leaf blades narrow, flat or rolled; ligule a line of hairs. Inflorescence an open or contracted panicle, sometimes reduced to a raceme. Spikelets large, wedge-shaped, laterally compressed, florets several, rachilla disarticulating above glumes and between florets; glumes subequal, as long as spikelet, membranous or papery, (1–)3–9-veined; floret callus short, obtuse; lemmas herbaceous or papery, 7–9-veined, pilose on margins or all over, apex 2-lobed, lobes acute or extended into slender awns; central awn arising from sinus, flat, column short, strongly twisted, bristle straight or sparsely twisted; palea equal to or shorter than its lemma. Lodicules 2, glabrous. Caryopsis with linear hilum up to 2/3 its length.
About 20 species: Asia, Europe, North and South America; two species in China.
Danthonia had a much broader circumscription in the past, including many species now placed in Rytidosperma. Species of Rytidosperma lack cleistogenes, and also differ from the above description in having lemma hairs in tufts, ciliate lodicules, and a punctiform hilum. Modern molecular studies have shown these two genera belong to different evolutionary lines. It is likely that the Himalayan species will be shown to be members of Rytidosperma, but some morphological characters are intermediate and the species have not yet been included in any molecular analysis. Further research is required to clarify their position.
