Digitaria violascens |
Digitaria cognata |
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violet crabgrass |
Carolina cottontop, Carolina crabgrass, fall crabgrass, fall witchgrass |
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Habit | Plants annual or of indefinite duration. | Plants perennial; cespitose, without rhizomes. |
Culms | 15-60 cm, erect, usually not branching from the upper nodes; nodes 3-4. |
30-56 cm, erect; nodes glabrous. |
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. |
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Leaves | mainly cauline; sheaths glabrous or sparsely to densely pubescent, sometimes with papillose-based hairs; ligules 0.2-1.5 mm, entire to lacerate; blades 2.4-12.6 cm long, 2-5.4 mm wide, glabrous or pubescent. |
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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. |
simple, 12.8-27.5 cm long, 16.5-44.5 cm wide, open; branches divergent; lower primary branches 10.5-24 cm, often with 1-several sterile branches near the base; pedicels divergent, spikelets solitary. |
Spikelets | 1.2-1.7 mm, homomorphic, narrowly elliptic. |
2.2-3.1 mm long, 0.7-1.1 mm wide, obovate or broadly 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 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. |
0.1-0.8 mm; upper glumes 1.8-2.8 mm, 3(5)-veined, glabrous or pubescent between the veins, hairs appearing as a narrow stripe; lower lemmas similar to the upper glumes in length, texture, and pubescence, 7-veined, veins unequally spaced, lateral veins closer together than the 3 central veins; upper lemmas 1.9-2.9 mm, glabrous, dark brown, narrowly acute; anthers 0.5-0.7 mm, yellow or purple. |
Caryopses | 1.3-1.6 mm. |
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2n | = 36. |
= 36. |
Digitaria violascens |
Digitaria cognata |
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Distribution |
AL; AR; FL; GA; IN; KY; LA; MA; MS; NC; OK; SC; TN; TX; HI; PR
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AL; AR; CT; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; MI; MN; MO; MS; NC; NE; NH; NJ; NY; OH; OK; PA; SC; TN; TX; VA; VT; WI; ON
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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 cognata grows in dry, sandy soils in the eastern portion of the Flora region from southern Ontario and Vermont through the United States and thence to southern Mexico. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 25, p. 372. | FNA vol. 25, p. 362. |
Parent taxa | Poaceae > subfam. Panicoideae > tribe Paniceae > Digitaria | Poaceae > subfam. Panicoideae > tribe Paniceae > Digitaria |
Sibling taxa | ||
Synonyms | Leptoloma cognatum | |
Name authority | Link | (Schult.) Pilg. |
Web links |