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Oldfield three-awn, prairie three-awn

Habit Plants annual.
Leaves

cauline;

sheaths usually shorter than the internodes, lowermost sheaths appressed-pilose basally;

collars glabrous;

ligules less than 0.5 mm;

blades usually 4-12 cm long, 0.5-1.5 mm wide, flat or loosely involute, somewhat lax, glabrous or scabridulous, pale green.

Inflorescences

spicate or racemose, (5)7-20 cm long, 2-4 cm wide;

primary branches rarely developed.

Spikelets

divergent, pedicels with axillary pulvini.

Glumes

unequal, glabrous, brownish-green with a purple tinge;

lower glumes (9)12-22(28) mm, 3-7-veined, midvein extended into a 1-13 mm awn between 2 delicate setae;

upper glumes (7)11-20(24) mm, 1-veined;

calluses 0.5-2 mm;

lemmas (9)12-22(23) mm, glabrous, light-colored, often mottled;

awns (8)12-65(70) mm, subequal, spreading;

anthers usually 1 and less than 0.5 mm, rarely 3 and 3-4 mm.

Caryopses

8-14 mm, brown.

Culm

25-55 cm, erect or geniculate at the base, highly branched.

2n

= 22.

Aristida oligantha

Poaceae tribe Aristideae

Distribution
from FNA
AL; AR; AZ; CA; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; NE; NH; NJ; NM; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; VA; VT; WI; WV; WY; BC; ON
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Discussion

Aristida oligantha grows in waste places, dry fields, roadsides, along railroads, and in burned areas, usually in sandy soil. It has been reported from Coahuila, Mexico, but is otherwise unknown outside southern Canada and the United States.

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

See subfamily description.

The tribe Aristideae has three genera and 300-350 species, and is primarily pan-tropical in its distribution. Its members are usually readily recognized by their terete, 3-awned lemmas with overlapping margins. Aristida, which has many more species than the other two genera combined, is the only genus found in the Americas.

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

Source FNA vol. 25, p. 326. FNA vol. 25, p. 314. Author: Kelly W. Allred;.
Parent taxa Poaceae > subfam. Aristidoideae > tribe Aristideae > Aristida Poaceae > subfam. Aristidoideae
Sibling taxa
A. adscensionis, A. arizonica, A. basiramea, A. californica, A. condensata, A. desmantha, A. dichotoma, A. divaricata, A. floridana, A. gypsophila, A. gyrans, A. havardii, A. lanosa, A. longespica, A. mohrii, A. palustris, A. pansa, A. patula, A. purpurascens, A. purpurea, A. ramosissima, A. rhizomophora, A. schiedeana, A. simpliciflora, A. spiciformis, A. stricta, A. ternipes, A. tuberculosa
Subordinate taxa
Name authority Michx. C.E. Hubb.
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