Aristida adscensionis |
Aristida mohrii |
|
---|---|---|
sixweeks three-awn, three awn |
Mohr's threeawn |
|
Habit | Plants short- to long-lived annuals. | Plants perennial; cespitose, bases knotty. |
Culms | (3)10-50(80) cm, often highly branched above the base. |
55-110 cm, erect, unbranched. |
Leaves | cauline, glabrous; sheaths shorter than the internodes, not disintegrating into threadlike fibers; ligules 0.4-1 mm; blades 2-14 cm long, 1-2.5 mm wide, flat to involute. |
cauline; sheaths shorter or longer than the internodes, glabrous, not disintegrating at maturity; collars glabrous, or sparsely pilose at the sides; ligules about 0.2 mm; blades 5-25 cm long, 1-2 mm wide, flat or loosely folded, pale green, cauline leaves usually glabrous adaxially, innovation leaves pilose. |
Inflorescences | panicles, 5-15(20) cm long, 0.5-3 cm wide, often interrupted below; nodes glabrous or with straight, less than 0.5 mm hairs; primary branches 1-4 cm, erect to ascending, without axillary pulvini, with 3-8 spikelets. |
spikelike racemes, 20-45 cm long, 1-2 cm wide; nodes glabrous, with only 1 spikelet. |
Spikelets | crowded. |
solitary, not overlapping. |
Glumes | unequal, 1-veined, acuminate; lower glumes 4-8 mm; upper glumes 6-11 mm; calluses 0.5-0.8 mm; lemmas 6-9 mm, slightly keeled, midveins scabrous, junction with the awns not evident; awns not disarticulating at maturity, flattened and straight to somewhat curved at the base, central rib flanked by equally wide pale wings; central awns 7-15(20) mm; lateral awns somewhat shorter, occasionally only 1-2 mm; anthers 3, 0.3-0.7 mm. |
9-11 mm, equal or the lower glumes slightly longer than the upper, narrowly oblong, often slightly falcate, tan to brown, 1-veined; lower glumes occasionally with 1-2 faint lateral veins, awn-tipped, awns about 0.5 mm; upper glume awned, awns 1-2.5 mm; calluses 1-1.5 mm; lemmas 7-10 mm, brown, lead-colored, or purplish, not beaked, junction with the awns not evident; awns equally thick, not disarticulating at maturity; central awns 14-20 mm, slightly longer than the lateral awns, strongly curved basally, distal portion reflexed; lateral awns horizontal to reflexed; anthers 3, about 4.5 mm, purplish. |
Caryopses | 4-5 mm, chestnut-colored. |
|
2n | = 22. |
= unknown. |
Aristida adscensionis |
Aristida mohrii |
|
Distribution |
AZ; CA; CO; KS; MD; MO; NE; NM; NV; NY; OK; SC; TX; UT; HI; PR; Virgin Islands
|
AL; FL; GA; SC |
Discussion | Aristida adscensionis grows in waste ground, along roadsides, and on degraded rangelands and dry hillsides, often in sandy soils. It is associated with woodland, prairie, and desert shrub communities. Its range extends from the United States south through Mexico and Central America to South America. Because Aristida adscensionis is highly variable in height, panicle size, and awn development, several varieties have been described. None are recognized here because most of the variation appears to be environmentally induced. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Aristida mohrii is endemic to the southeastern United States, growing on dry, sandy pinelands and oak barrens, and occasionally in waste places. It is sometimes confused with A. simpliciflora because both have reduced, spikelike inflorescences, but A. simpliciflora has lateral awns that are only about half as thick as the central awn, and its spikelets are borne in pairs. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 25, p. 330. | FNA vol. 25, p. 337. |
Parent taxa | Poaceae > subfam. Aristidoideae > tribe Aristideae > Aristida | Poaceae > subfam. Aristidoideae > tribe Aristideae > Aristida |
Sibling taxa | ||
Synonyms | A. interrupta, A. bromoides, A. adscensionis var. modesta | |
Name authority | L. | Nash |
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