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fingergrass, Henry's crabgrass, kukaepua'a, saulangi, smooth crabgrass, southern crab grass, tropical crabgrass

shortleaf crabgrass

Habit Plants annual or of indefinite duration. Plants perennial; rhizomatous, rhizomes short, giving the plants hard, knotty, much-branched bases.
Culms

10-100 cm long, erect portion 30-60 cm, long-decumbent, rooting and branching at the decumbent nodes, sparingly branched or unbranched from the upper nodes;

nodes 2-5, glabrous.

20-55 cm, erect, sometimes geniculate, not rooting at the lower nodes.

Sheaths

with papillose-based hairs;

ligules 2-3.5 mm, erose;

blades 1.5-14.4(18.9) cm long, 3-9 mm wide, flat, glabrous, a few scattered papillose-based hairs at the base of the adaxial surfaces (occasionally over the whole adaxial surface), usually also scabrous on both surfaces.

Panicles

with 2-10 spikelike primary branches, these digitate or in 1-3 whorls on rachises to 2 cm;

lowest panicle nodes with hairs more than 0.4 mm;

primary branches 3-24 cm long, 0.6-1.2(2) mm wide, glabrous or with less than 1 mm hairs, axes wing-margined, wings at least 1/2 as wide as the midribs, lower and middle portions of the branches bearing spikelets in unequally pedicellate pairs;

secondary branches absent;

shorter pedicels 0.5-1 mm;

longer pedicels 1.5-4 mm.

with 3-6 spikelike primary branches on 6-10(15) cm rachises;

primary branches 1-6 cm, not or only narrowly winged, bearing spikelets in unequally pedicellate pairs, pedicels not adnate to the branch axes;

shorter pedicels 1.5-2 mm;

longer pedicels 3-4 mm.

Spikelets

(2.7)2.8-4.1 mm long, homomorphic.

homomorphic, 2.5-3.1 mm (including pubescence), 2.4-3 mm (excluding pubescence).

Caryopses

2.1-3.4 mm.

Lower

glumes 0.2-0.8 mm, acute;

upper glumes (1.2)1.5-2.7 mm, about 2/3 to almost as long as the spikelet, 3-veined, margins and apices pilose;

lower lemmas 2.7-4.1 mm, 7-veined, veins unequally spaced, outer 3 veins crowded together near each margin, well-separated from the midvein, usually smooth, occasionally the lateral veins scabridulous on the distal 1/3 margins and regions between the 2 inner lateral veins hairy, hairs 0.5-1 mm (rarely glabrous), sometimes also with glassy yellow hairs between the 2 inner lateral veins, these more common on the upper spikelets;

upper lemmas 2.5-4 mm, glabrous, yellow, tan, or gray when immature, becoming brown, often purple-tinged (occasionally completely purple) at maturity;

anthers 0.6-1 mm.

glumes 0.3-1 mm, veinless;

upper glumes 2.1-3 mm (including pubescence), as long as or exceeding the upper florets by no more than 0.5 mm, 3-veined, densely appressed-pubescent, hairs 0.5-1 mm, white to purple, tapering or parallel-sided, not spreading at maturity;

lower lemmas 2.3-3.1 mm (including pubescence), as long as or exceeding the upper lemmas by up to 0.5 mm, 5-veined, veins equally spaced, intercostal regions densely appressed-pubescent, hairs 0.5-1 mm, white to purple, tapering or parallel-sided, not spreading at maturity;

upper lemmas 2.2-2.5 mm, brown when immature, dark brown at maturity.

Basal

sheaths tomentose;

culm sheaths glabrous or variously pubescent (puberulent, ciliate, or sparsely hirsute);

ligules (0.1)0.5-1(1.5) mm, ciliate;

blades 2-5.5 cm long, 2-3 mm wide.

2n

= 54.

= 36.

Digitaria ciliaris

Digitaria hitchcockii

Distribution
from FNA
AL; AR; AZ; CA; CT; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; MO; MS; NC; NE; NJ; NM; NY; OH; OK; PA; SC; TN; TX; UT; VA; HI; PR; Virgin Islands
[WildflowerSearch map]
[BONAP county map]
from FNA
TX; Virgin Islands
[BONAP county map]
Discussion

Digitaria ciliaris is a weedy species, found in open, disturbed areas in most warm-temperate to tropical regions, primarily in the eastern United States. It is particularly abundant in the Southeast. So far as is known, the two varieties distinguished in the following key do not differ in any other characters. They are recognized here pending further study.

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

Digitaria hitchcockii is an uncommon species of open, dry, gravelly slopes in southwestern Texas and northern Mexico.

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

Key
1. Lower lemmas without glassy yellow hairs
var. ciliaris
1. Lower lemmas with glassy yellow hairs
var. chrysoblephara
Source FNA vol. 25, p. 382. FNA vol. 25, p. 366.
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. 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. 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. 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
Subordinate taxa
D. ciliaris var. chrysoblephara, D. ciliaris var. ciliaris
Name authority (Retz.) Koeler (Chase) Stuck.
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