Aristida oligantha |
Poaceae tribe Aristideae |
|
---|---|---|
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 |
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
|
|
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. |
Parent taxa | ||
Sibling taxa | ||
Subordinate taxa | ||
Name authority | Michx. | C.E. Hubb. |
Web links |
|