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

sourgrass

longleaf crabgrass

Habit Plants perennial; cespitose, shortly rhizomatous, with knotty bases. Plants perennial; in dense tufts, not rhizomatous.
Culms

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

60-100 cm, erect.

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.

villous, particularly the lower sheaths;

ligules 0.2-0.4, fimbriate;

blades to 47 cm long, 1-2.1 mm wide, involute, glabrous and smooth abaxially, scabrous adaxially, sometimes with a few long hairs near the base.

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.

of 2-3(5) spikelike primary branches on elongate rachises;

primary branches 8-13(20) cm, narrowly winged, wings no more than 1/2 as wide as the midribs, bearing spikelets in unequally pedicellate groups of 3-4(5);

secondary branches rarely present;

longest pedicels to 5 mm.

Spikelets

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

1.7-2.3 mm, elliptical, glabrous.

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 0.9-1 mm, less than 1/2 as long as the spikelets, 3-veined, glabrous, broadly rounded to truncate;

lower lemmas slightly shorter than the spikelets, 5-veined, glabrous;

upper lemmas smooth, brown when immature, dark brown at maturity.

2n

= 36.

= unknown.

Digitaria insularis

Digitaria gracillima

Distribution
from FNA
AL; AZ; FL; IL; MS; TX; HI; PR; Virgin Islands
[WildflowerSearch map]
[BONAP county map]
from FNA
FL
[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 gracillima is a rare species, endemic to scrub and dry pinelands of peninsular Florida. It was formerly interpreted as including D. bakeri, but differs from that species both morphologically and ecologically.

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

Source FNA vol. 25, p. 370. FNA vol. 25, p. 364.
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. 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 Trichachne insularis
Name authority (L.) Mez ex Ekman (Scribn.) Fernald
Web links