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

slender crabgrass

Habit Plants annual or of indefinite duration. Plants annual, or short-lived perennials; cespitose, not rhizomatous.
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.

(10)25-150 cm, erect or decumbent, branching, sometimes rooting at the lower nodes;

nodes 3-6.

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.

keeled, basal sheaths usually with papillose-based hairs, rarely glabrous;

ligules 0.3-1.5 mm;

blades 2-18 cm long, 1-6 mm wide, flat or involute, glabrous, scabrous, or pilose.

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 2-7 spikelike primary branches, these digitate or the rachises to 1 cm;

longest primary branches 20-25 cm, axes triquetrous, not winged, with spikelets in unequally pedicellate groups of 3(-5) on the basal ½ (J.

Spikelets

(2.7)2.8-4.1 mm long, homomorphic.

1.3-2.8 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 absent or to 0.1 mm;

upper glumes 1-2 mm long, from 3/4 to almost as long as the spikelets, almost glabrous or sparsely to densely pubescent with clavate to capitate hairs (use 20x magnification), glume apices rounded;

lower lemmas equaling the spikelets, glabrous or glandular-pubescent, 5-7-veined, veins unequally spaced, outer 3 veins on each side closer to each other than the midvein is to the inner lateral veins;

upper lemmas 1.3-2 mm, apiculate, dark brown at maturity;

anthers 0.3-0.6 mm.

Wipff

, pers.

Comm

.).

2n

= 54.

= 36, 54.

Digitaria ciliaris

Digitaria filiformis

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
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from FNA
AL; AR; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; MI; MO; MS; NC; NH; NJ; NY; OH; OK; PA; RI; SC; TN; TX; VA; VT; WV
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[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 filiformis grows throughout the warmer parts of the eastern United States, van filifomis the most widespread of its varieties, extending into 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
1. Lower lemmas glabrous
var. laeviglumis
1. Lower lemmas pubescent.
→ 2
2. Basal leaf sheaths glabrous; cauline blades about 1 mm wide, folded or involute
var. dolichophylla
2. Basal leaf sheaths with papillose-based hairs; cauline blades 1-6 mm wide, flat.
→ 3
3. Spikelets 1.3-1.9 mm long; panicle branches 3-13 cm long; culms 10-80 cm tall
var. filiformis
3. Spikelets 2-2.8 mm long; panicle branches 10-25 cm long; plants 75-150 cm tall
var. villosa
Source FNA vol. 25, p. 382. 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. 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. 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
Subordinate taxa
D. ciliaris var. chrysoblephara, D. ciliaris var. ciliaris
D. filiformis var. dolichophylla, D. filiformis var. filiformis, D. filiformis var. laeviglumis, D. filiformis var. villosa
Synonyms Syntherisma filiformis
Name authority (Retz.) Koeler (L.) Koeler
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