Digitaria ciliaris |
Digitaria arenicola |
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fingergrass, Henry's crabgrass, kukaepua'a, saulangi, smooth crabgrass, southern crab grass, tropical crabgrass |
sand crabgrass, sand witchgrass |
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Habit | Plants annual or of indefinite duration. | Plants perennial; loosely tufted, with long, creeping rhizomes. | ||||
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. |
20-60 cm, erect; lower nodes glabrous or pubescent; upper nodes glabrous. |
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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. |
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Leaves | mainly cauline; sheaths usually glabrous, lower sheaths sometimes pubescent; ligules 0.4-1 mm, truncate, entire to lacerate; blades 5-11.5 cm long, 3-4.5 mm wide, glabrous, usually flat or folded. |
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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. |
simple, 12-24 cm long, 19-40 cm wide, open; nodes hispid; branches divergent; lower primary branches 10-21 cm, with 1-several sterile branches near the base; pedicels divergent, spikelets solitary. |
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Spikelets | (2.7)2.8-4.1 mm long, homomorphic. |
3.5-4.6 mm long, 0.8-1 mm wide, elliptical. |
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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. |
0.2-0.5 mm; upper glumes 3-3.8 mm, 5-7-veined, densely villous between the veins, hairs white, becoming purple at maturity; lower lemmas similar to the upper glumes in size, texture, and pubescence; upper lemmas 3-3.7 mm, narrowly acute, dark brown; anthers 1.1-1.4 mm. |
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Caryopses | 1.5-2 mm. |
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2n | = 54. |
= 36, 37. |
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Digitaria ciliaris |
Digitaria arenicola |
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Distribution |
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
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TX |
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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 arenicola is endemic to deep sands along the coast of Texas, a very restricted habitat and one that is being lost to the development of coastal parks and housing. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 25, p. 382. | FNA vol. 25, p. 362. | ||||
Parent taxa | ||||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Leptoloma arenicola | |||||
Name authority | (Retz.) Koeler | (Swallen) Beetle | ||||
Web links |