[Andropogon vimineus Trin., moreEulalia viminea var. imberbis (Nees ex Steud.) Kuntze, Microstegium imberbe (Nees ex Steud.) Tzvelev, Microstegium nodosum , Microstegium vimineum var. willdenowianum (Nees ex Steud.) A. Camus, Microstegium willdenovianum Nees, Microstegium willdenowianum Nees ex Steud., Pollinia imberbis Nees ex Steud., Pollinia imberbis var. willdenowiana (Nees ex Steud.) Hack., Pollinia viminea (Trin.) Merr., Pollinia willdenowiana (Nees ex Steud.) Benth.]
Plants annual. Culms 40-100 cm tall, 1-1.5 mm thick, freely branching,
lower portions prostrate, rooting at the nodes, terminal portions and flowering
branches erect; nodes glabrous. Sheaths shorter than the internodes,
mostly glabrous or sparsely pubescent above, margins ciliate, becoming pilose
at the throat; ligules 0.5-0.8 mm, truncate; blades 3-10 cm long,
8-15 mm wide, glabrous or sparsely pubescent, bases cuneate, midveins white, apices
attenuate, acute. Cleistogamous inflorescences concealed in the upper sheaths;
chasmogamous inflorescence exserted, of (1)2-4(6) racemose to subdigitate,
erect to ascending rames; rames 3-7 cm, glaucous-green; internodes
3.5-5 mm, gradually widened above, ciliate. Spikelets 3.7-6.5 mm. Lower
glumes2-keeled, subtruncate to shallowly 2-toothed; upper glumes acute;
upper lemmas usually awned, awns 2-5(15) mm, often concealed by the glumes; anthers
3, 0.7-1 mm. Pedicels 3-4 mm. 2n = 40.
Microstegium vimineum was introduced to Tennessee from Asia around 1919
and is now established in much of the eastern United States. Although often associated
with forested and wetland areas, it also does well in many disturbed areas. In
suitable habitats it quickly spreads by rooting from its prostrate culms, forming
dense, monospecific stands. It is sometimes confused with Leersia viriginica,
but differs from that species in its glabrous cauline nodes and the presence of
hairs at the summit of the leaf sheaths. In addition, M. vimineum flowers
in late September and October and is clearly a member of the Andropogoneae,
whereas L. viriginica flowers in June through July and is a member of the
Oryzeae.
Straggling annual 6-10 dm; blades lanceolate, 5-8 cm, racemes 2-5 cm, approximate, few in the panicle; pedicel flattened, ciliate; glumes 5 mm, awnless; lemmas shorter than the glumes, the fertile one awnless or often with a slender awn 4-8 mm; 2n=40. Native of trop. Asia, from N.J., Pa., and O. southward. (Eulalia v.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
