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violet crabgrass

Carolina cottontop, Carolina crabgrass, fall crabgrass, fall witchgrass

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.

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.

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.

2n

= 36.

= 36.

Digitaria violascens

Digitaria cognata

Distribution
from FNA
AL; AR; FL; GA; IN; KY; LA; MA; MS; NC; OK; SC; TN; TX; HI; PR
[WildflowerSearch map]
[BONAP county map]
from FNA
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
[WildflowerSearch map]
[BONAP county map]
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
D. abyssinica, D. arenicola, D. bakeri, D. bicornis, D. californica, D. ciliaris, D. cognata, D. didactyla, D. eriantha, D. filiformis, D. floridana, D. gracillima, D. hitchcockii, D. horizontalis, D. insularis, D. ischaemum, D. leucocoma, D. longiflora, D. milanjiana, D. nuda, D. patens, D. pauciflora, D. pubiflora, D. sanguinalis, D. serotina, D. setigera, D. simpsonii, D. texana, D. tomentosa, D. velutina
D. abyssinica, D. arenicola, D. bakeri, D. bicornis, D. californica, D. ciliaris, D. didactyla, D. eriantha, D. filiformis, D. floridana, D. gracillima, D. hitchcockii, D. horizontalis, D. insularis, D. ischaemum, D. leucocoma, D. longiflora, D. milanjiana, D. nuda, D. patens, D. pauciflora, D. pubiflora, D. sanguinalis, D. serotina, D. setigera, D. simpsonii, D. texana, D. tomentosa, D. velutina, D. violascens
Synonyms Leptoloma cognatum
Name authority Link (Schult.) Pilg.
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