Digitaria insularis |
Digitaria texana |
|
---|---|---|
sourgrass |
Texas crabgrass |
|
Habit | Plants perennial; cespitose, shortly rhizomatous, with knotty bases. | Plants perennial; not rhizomatous. |
Culms | 80-130 cm, erect, with densely villous cataphylls, branching from the lower and middle nodes. |
30-80 cm, sometimes erect, usually decumbent and branching and rooting at the lower nodes, not branching at the upper nodes. |
Sheaths | usually sparsely to densely papillose-hirsute, occasionally glabrous; ligules 4-6 mm, usually lacerate, not ciliate; blades 20-50 cm long, 10-17 mm wide, lax, smooth or scabridulous abaxially, scabridulous to scabrous adaxially. |
of the lower leaves villous, those of the upper leaves sometimes glabrous, those of the flag leaves without axillary panicles; ligules 1.5-2 mm; blades 10-15 cm long, 2-7 mm wide, hirsute to nearly glabrous. |
Panicles | 20-35 cm long, 2-10 cm wide, with numerous spikelike primary branches; primary branches 10-15 cm, appressed to ascending at maturity, axes not wing-margined or with wings less than 1/2 as wide as the midribs; internodes 3-4.5(6) mm (midbranch), bearing spikelets in unequally pedicellate pairs; secondary branches rarely present; pedicels not adnate to the branches; shorter pedicels 0.7-2 mm; longer pedicels 2.5-5 mm; terminal pedicels 2-5 mm. |
with 5-10 spikelike primary branches on 1-4 cm rachises; primary branches 5-10(13) cm, axes triquetrous, narrowly winged, wings less than 1/2 as wide as the midribs, lower and middle portions of the branches bearing paired spikelets; secondary branches rarely present. |
Spikelets | 5.5-8.2 mm (including pubescence), 4.2-5.9 mm (excluding pubescence), narrowly ovate, acuminate. |
2-3.6 mm, narrowly ovate-oblong, acute. |
Caryopses | narrowly oblong. |
|
Lower | glumes 0.6-0.8 mm; upper glumes 3.5-4.5 mm, 3-5-veined, pubescent on the margins; lower lemmas 4.1-5.7 mm (exceeded 1.5-5 mm by pubescence), narrowly ovate, 7-veined, pubescent between most, sometimes all, of the veins and on the margins, veins usually obscured by a dense covering of golden-brown hairs, hairs 3-6 mm, spreading at maturity, intercostal regions on either side of the midvein glabrous or pubescent with shorter, fine, white hairs, sometimes intermixed with the golden-brown hairs; upper lemmas 3.2-4.5 mm, narrowly ovate, brown when immature, dark brown at maturity, acuminate; anthers 1-1.2 mm. |
glumes absent; upper glumes almost as long as the spikelets, 3(5)-veined, shortly villous on the margins and sometimes between the margins; lower lemmas similar to the upper glumes; upper lemmas gray or yellow, sometimes purple-tinged, becoming purple at maturity. |
2n | = 36. |
= 54. |
Digitaria insularis |
Digitaria texana |
|
Distribution |
AL; AZ; FL; IL; MS; TX; HI; PR; Virgin Islands
|
FL; TX |
Discussion | Digitaria insularis grows in low, open ground of the southern United States, and extends to the West Indies, Mexico, and through Central America to Argentina. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Digitaria texana grows in sandy oak woods and prairies of southern Texas and Florida. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 25, p. 370. | FNA vol. 25, p. 374. |
Parent taxa | Poaceae > subfam. Panicoideae > tribe Paniceae > Digitaria | Poaceae > subfam. Panicoideae > tribe Paniceae > Digitaria |
Sibling taxa | ||
Synonyms | Trichachne insularis | |
Name authority | (L.) Mez ex Ekman | Hitchc. |
Web links |