The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

sourgrass

East Indian crabgrass

Habit Plants perennial; cespitose, shortly rhizomatous, with knotty bases. Plants of indefinite duration.
Culms

80-130 cm, erect, with densely villous cataphylls, branching from the lower and middle nodes.

to 120 cm tall, bases long-decumbent and rooting at the lower 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.

with papillose-based hairs;

ligules 2.5-3.5 mm;

blades 4-28 cm long, 4-12 mm wide, scabrous, usually with some scattered papillose-based hairs on the base of the adaxial surfaces, sometimes with hairs all over.

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 3-11 spikelike primary branches in 1-several whorls, rachises to 6 cm;

primary branches 5-15 cm, axes wing-margined, wings more than 1/2 as wide as the midribs, lower and middle portions bearing spikelets in unequally pedicellate pairs;

secondary branches absent;

shorter pedicels 0.3-0.8 mm;

longer pedicels 1.7-2.7 mm.

Spikelets

5.5-8.2 mm (including pubescence), 4.2-5.9 mm (excluding pubescence), narrowly ovate, acuminate.

2.4-3.5 mm, homomorphic, ovate.

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 or to 0.1 mm;

upper glumes 0.2-1.3 mm, 1/6 - 1/3 as long as the spikelets, 1-3-veined, margins and apices with appressed, white hairs about 0.5 mm, truncate or bilobed;

lower lemmas (5)7-veined, veins smooth or scabrous only over the distal 1/3, unequally spaced, margins and lateral intercostal regions silky-ciliate;

upper lemmas tan or gray when immature, brown at maturity, acuminate;

anthers 0.6-1.3 mm.

2n

= 36.

= 70, 72.

Digitaria insularis

Digitaria setigera

Distribution
from FNA
AL; AZ; FL; IL; MS; TX; HI; PR; Virgin Islands
[WildflowerSearch map]
[BONAP county map]
from FNA
FL; HI; PR
[BONAP county map]
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 setigera is native to southeastern Asia. It is now established in tropical America, growing in disturbed habitats in Florida and Central America, and probably in tropical South America. It has often been confused with D. sanguinalis.

Plants in the Flora region belong to Digitaria setigera Roth var. setigera. Unlike plants of D. setigera var. calliblepharata (Henrard) Veldkamp, they do not have large, glassy hairs on their lower lemmas.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 25, p. 370. FNA vol. 25, p. 382.
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. 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
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. simpsonii, D. texana, D. tomentosa, D. velutina, D. violascens
Synonyms Trichachne insularis
Name authority (L.) Mez ex Ekman Roth
Web links