矮小柳叶箬 ai xiao liu ye ruo

Isachne dispar Trinius; I. heterantha Hayata; Panicum bellum Steudel, nom. illeg. superfl.; Sphaerocaryum pulchellum (Roth) Merrill; Steudelella pulchella (Roth) Honda.

Annual. Culms very slender, straggling, branching and rooting at lower nodes, 10–25 cm tall, nodes hispid with a glandular ring below. Leaf sheaths shorter than internodes, papillose-hispid at base above node, otherwise pilose or subglabrous, outer margin ciliate; leaf blades ovate or ovate-lanceolate, 2–3 × 0.8–1 cm, scabrid to thinly hispid, base cordate-amplexicaul with pectinate margin, apex shortly acuminate; ligule ca. 2 mm. Panicle narrowly ovate to pyramidal in outline, 2.5–5 cm, glandular; primary branches inserted singly, stiffly and regularly spreading with branchlets to their base; pedicels mostly shorter than spikelets. Spikelets plumply elliptic, 1.3–1.8(–2) mm, gray-green or purplish green; florets clearly dissimilar; lower floret male, upper floret bisexual or female; glumes slightly shorter than lower floret; lower glume elliptic-oblong, 5-veined, upper glume broadly elliptic, 7-veined both glabrous, apex obtuse; lower lemma herbaceous, elliptic-oblong, dorsally flattened, smooth, glabrous; anthers 0.3–0.5 mm; upper lemma slightly shorter, crustaceous, strongly plano-convex, pubescent. Fl. and fr. May–Oct.

Marshy ground and shallow water, gregarious and forming patches. Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hunan, Jiangxi, Taiwan, Yunnan, Zhejiang [Bangladesh, India, Malaysia, Nepal, Thailand, Vietnam].

The description in Roemer and Schultes (1817) was taken from the manuscript of Roth (Nov. Pl. Sp. 58. 1821).

This taxon grades into small, slender forms of Isachne globosa and is sometimes included within that species (as the synonym I. dispar). However, this creates an unacceptably wide range of variation within I. globosa. Typical forms of I. pulchella are quite different from typical forms of I. globosa. Isachne pulchella, as recognized here, comprises small, delicate plants with short, broad leaf blades, hairy nodes with a glandular ring below, small spikelets with clearly dissimilar florets, a soft, herbaceous lower floret lacking a dorsal groove, and a pubescent upper floret. The anthers are shorter than in small forms of I. globosa.