Plants annual or of indefinite duration. Culms 15-60 cm, erect,
usually not branching from the upper nodes; nodes 3-4. Sheaths
glabrous or sparsely pubescent; ligules 0.6-2.5 mm; blades 1.5-9
cm long, 3-5 mm wide, glabrous, with papillose-based hairs basally. Panicles
with 2-7 spikelike primary branches in 1-2 verticils; primary branches
3-12 cm, erect to ascending, axes 0.6-1 mm wide, wing-margined, wings at least
1/2 as wide as the midribs, lower and middle portions of the branches with spikelets
in groups of 3(4, 5); secondary branches rarely present; axillary
inflorescences absent. Spikelets 1.2-1.7 mm, homomorphic, narrowly
elliptic. Lower glumes absent or a veinless, membranous rim; upper
glumes 1.2-1.4 mm, 1/2 as long as to almost equaling the upper lemmas, 3-veined,
appressed-pubescent, hairs minutely verrucose; lower lemmas 1.2-1.7 mm,
5-7-veined, veins equally spaced, region between the 2 inner lateral veins and
the margins appressed-pubescent, hairs 0.3-0.5 mm, smooth or minutely verrucose
(use 50× magnification), verrucose hairs most abundant near the lemma
bases; upper lemmas light brown when immature, dark brown at maturity;
anthers 0.4-0.6 mm. 2n = 36.
Digitaria violascens is a weedy species that is native to tropical regions
of the Eastern Hemisphere. It is now established in the Flora region,
primarily in the southeastern United States, and in Mexico and Central America.
It grows in disturbed sites.
Distinguished from no. 2 [Digitaria ischaemum (Schreb.) Muhl.] by the somewhat smaller (1.5 mm), less pubescent spikelets, the hairs not capitellate, the second glume slightly shorter; 2n=36. Pantropical, extending into our range in Ky. and s. Ind.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
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