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knot-root bristlegrass, knotroot foxtail, marsh bristle grass, yellow bristlegrass

green bristle grass, green foxtail, setaire verte

Habit Plants perennial; rhizomatous, rhizomes short, knotty. Plants annual.
Culms

30-120 cm;

nodes glabrous.

20-250 cm;

nodes glabrous.

Sheaths

glabrous;

ligules shorter than 1 mm, of hairs;

blades to 25 cm long, 2-8 mm wide, flat, scabrous above.

glabrous, sometimes scabridu-lous, margins ciliate distally;

ligules 1-2 mm, ciliate;

blades to 20 cm long, 4-25 mm wide, flat, scabrous or smooth, glabrous.

Panicles

3-8 (10) cm, of uniform width throughout their length, densely spikelike;

rachises scabro-hispid;

bristles 4-12, 2-12 mm, antrorsely barbed, yellow to purple.

3-20 cm, densely spicate, nodding only from near the apices;

rachises hispid and villous;

bristles 1-3, 5-10 mm, antrorsely scabrous, usually green, rarely purple.

Spikelets

2-2.8 mm, elliptical and turgid.

1.8-2.2 mm.

Lower

glumes about 1/3 as long as the spikelets, 3-veined;

upper glumes 1/2 - 2/3 as long as the spikelets, 5-veined;

lower florets often staminate;

lower lemmas occasionally indurate and faintly transversely rugose;

lower paleas equaling the lower lemmas;

upper lemmas distinctly transversely rugose, often purple-tipped.

glumes about as long as the spikelets, triangular-ovate, 3-veined;

upper glumes nearly equaling the upper lemmas, elliptical, 5-6-veined;

lower lemmas slightly exceeding the upper lemmas, 5-veined;

lower paleas about as long as the lower lemmas, hyaline;

upper lemmas very finely and transversely rugose, pale green, 5-6-veined;

upper paleas similar to the upper lemmas.

2n

= 36, 72.

= 18.

Setaria parviflora

Setaria viridis

Distribution
from FNA
AL; AR; AZ; CA; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; MO; MS; NC; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; TN; TX; UT; VA; WA; WV; HI; PR; Virgin Islands
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from FNA
AK; AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; LB; MB; NB; NS; NT; ON; PE; QC; SK; YT
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[BONAP county map]
Discussion

Setaria parviflora is a common, native species of moist ground. It is most frequent along the Atlantic and Gulf coasts, but it also grows from the Central Valley of California east through the central United States and southward through Mexico to Central America, as well as in the West Indies. The plant from Oregon was found on a ballast dump; the species is not established in that state.

Setaria parviflora is the most morphologically diverse and widely distributed of the indigenous perennial species of Setaria.

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

Setaria viridis resembles S. italica but differs in its shorter spikelets and rugose upper florets, and mode of disarticulation. It is also a more aggressive weed. It is native to Eurasia but is now widespread in warm temperate regions of the world.

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

Key
1. Culms 100-250 cm tall; blades 10-25 mm wide; panicles 10-20 cm long
var. major
1. Culms 20-100 cm tall; blades 4-12 mm wide; panicles 3-8 cm long
var. viridis
Source FNA vol. 25, p. 556. FNA vol. 25, p. 554.
Parent taxa Poaceae > subfam. Panicoideae > tribe Paniceae > Setaria > subg. Setaria Poaceae > subfam. Panicoideae > tribe Paniceae > Setaria > subg. Setaria
Sibling taxa
S. adhaerans, S. arizonica, S. barbata, S. chapmanii, S. corrugata, S. faberi, S. grisebachii, S. italica, S. leucopila, S. liebmannii, S. macrosperma, S. macrostachya, S. magna, S. megaphylla, S. palmifolia, S. pumila, S. rariflora, S. reverchonii, S. scheelei, S. setosa, S. sphacelata, S. texana, S. verticillata, S. verticilliformis, S. villosissima, S. viridis
S. adhaerans, S. arizonica, S. barbata, S. chapmanii, S. corrugata, S. faberi, S. grisebachii, S. italica, S. leucopila, S. liebmannii, S. macrosperma, S. macrostachya, S. magna, S. megaphylla, S. palmifolia, S. parviflora, S. pumila, S. rariflora, S. reverchonii, S. scheelei, S. setosa, S. sphacelata, S. texana, S. verticillata, S. verticilliformis, S. villosissima
Subordinate taxa
S. viridis var. major, S. viridis var. viridis
Synonyms S. imberbis, S. gracilis, S. geniculata
Name authority (Poir.) Kerguelen (L.) P. Beauv.
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