Digitaria violascens |
Digitaria bicornis |
|
---|---|---|
violet crabgrass |
Asian crabgrass |
|
Habit | Plants annual or of indefinite duration. | Plants of indefinite duration; sometimes stoloniferous. |
Culms | 15-60 cm, erect, usually not branching from the upper nodes; nodes 3-4. |
with erect portion 10-85 cm, long-decumbent, rooting and branching at the lower nodes. |
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. |
with papillose-based hairs or the upper sheaths glabrous; ligules 1-4 mm; blades 3-14 cm long, 2-9 mm wide, mostly glabrous but the adaxial surfaces 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 bearing spikelets in groups of 3(4, 5); secondary branches rarely present; axillary inflorescences absent. |
with (2)3-6 spikelike primary branches, these digitate or a few solitary branches below; lowest nodes glabrous or with hairs less than 0.4 mm; primary branches 6.5-21 cm long, 0.6-1.3 mm wide, axes winged, wings at least 1/2 as wide as the midribs, lower and middle portions bearing spikelets in unequally pedicellate pairs, pedicels not adnate to the branches; secondary branches absent; shorter pedicels about 0.2 mm; longer pedicels to 2 mm. |
Spikelets | 1.2-1.7 mm, homomorphic, narrowly elliptic. |
2.6-3.7 mm, spikelet pairs dimorphic in their pubescence and venation pattern of the lower lemmas. |
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 50x 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. |
absent or to 0.9 mm, deltoid or bifid; upper glumes 1.7-2.8 mm, 1/2 - 3/4 as long as the spikelets, 3-veined; lower lemmas 7-veined, veins smooth; lower lemmas of shortly pedicellate spikelets with 3 equally spaced, glabrous or shortly pubescent central veins, lemma margins and the region between the 2 lateral veins with appressed or spreading, 0.5-1 mm hairs; lower lemmas of long-pedicellate spikelets with unequally spaced veins, midvein well-separated from the 3 lateral veins, lateral veins crowded together near the margins, lemma margins and the region between the 2 inner lateral veins hairy with appressed or strongly divergent, 1-2 mm hairs, sometimes also with longer, glassy yellow hairs; upper lemmas of all spikelets usually yellow or gray, sometimes light brown, at maturity; anthers 0.5-0.6 mm. |
2n | = 36. |
= 54, 72. |
Digitaria violascens |
Digitaria bicornis |
|
Distribution |
AL; AR; FL; GA; IN; KY; LA; MA; MS; NC; OK; SC; TN; TX; HI; PR
|
AL; FL; GA; IA; LA; MS; NC; SC; TX; VA; PR |
Discussion | 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 south-eastern United States, and in Mexico and Central America. It grows in disturbed sites. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Digitaria bicornis is a common species on the sandy coastal plain of the southeastern United States. Its range extends through Mexico to Costa Rica and northern South America, as well as to the West Indies. The Californian record reflects a 1926 collection; the species is not known to be established in the state. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 25, p. 372. | FNA vol. 25, p. 380. |
Parent taxa | Poaceae > subfam. Panicoideae > tribe Paniceae > Digitaria | Poaceae > subfam. Panicoideae > tribe Paniceae > Digitaria |
Sibling taxa | ||
Name authority | Link | (Lam.) Roem. & Schult. |
Web links |