Nassella trichotoma |
Nassella cernua |
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serrated tussock, serrated tussockgrass, yass tussockgrass |
cernuous nassella, nodding needlegrass, nodding tussockgrass |
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Habit | Plants perennial; cespitose, not rhizomatous. | Plants perennial; cespitose, not rhizomatous. |
Culms | 20-60 cm tall, about 1 mm thick, erect, internodes glabrous; nodes 2-4, pubescent. |
30-100 cm tall, 1-2.2 mm thick, erect or geniculate at the basal nodes, |
Sheaths | glabrous, smooth; collars glabrous, without tufts of hair at the sides; ligules 0.5-2.5 mm, glabrous, obtuse; blades 15-45 cm long, 0.2-0.6 mm wide, convolute, stiff, scabridulous. |
|
Leaves | usually glaucous; sheaths mostly glabrous, throats ciliate; collars mostly glabrous, with sparse tufts of hair at the sides, hairs 1-1.6 mm; ligules 0.2-1.6 mm, glabrous, truncate to rounded; blades 3-26 cm long, 0.4-1.2 mm wide, flat to convolute, abaxial surfaces scabridulous, adaxial surfaces hairy. |
|
Panicles | 8-25 cm, open, lax, sparse; branches 2-6 cm, with 1-8 spikelets; pedicels 3-12 mm. |
15-80 cm, open, often partially enclosed at maturity; branches 1-6 cm, flexuous or cernuous, with 1-8 spikelets on the distal 1/2; pedicels 3-9 mm. |
Glumes | subequal, 4-10 mm long, 0.9-1.2 mm wide, narrowly lanceolate, scabridulous, apices aristate; florets 1.5-2.5 mm long, 0.7-0.9 mm wide, terete, widest near the top; calluses 0.1-0.3 mm, acute, strigose, hairs reaching to midlength on the lemmas; lemmas strongly tuberculate, particularly distally, mostly glabrous, narrowing abruptly to the crown, midveins pubescent proximally; crowns about 0.5 mm long, about 0.2 mm wide, straight-sided, rims entire or irregularly lacerate, glabrous; awns 15-35 mm, eccentric, straight to twice-geniculate; anthers 3, 1-1.5 mm. |
glabrous, narrowly lanceolate, acuminate; lower glumes 12-22 mm long, 0.9-1.7 mm wide; upper glumes 3-4 mm shorter that the lower glumes; florets 4-9 mm long, 0.6-0.8 mm wide, terete; calluses 1.4-3.6 mm, sharp, strigose; lemmas minutely papillose, tapering to the crown, the proximal 1/4 evenly pubescent, the distal 3/4 pubescent only over the veins; crowns 0.2-0.5 mm long, 0.3-0.35 mm wide, straight-sided, rims with 0.8-1.1 mm hairs; awns 50-110 mm long, 0.2-0.3 mm thick at the base, first geniculation evident, second geniculation obscure, terminal segment cernuous; anthers 3.5-5.5 mm, penicillate. |
Caryopses | about 1.2 mm, oblong, dark brown. |
4.5-5.5 mm. |
2n | = 36. |
= 70. |
Nassella trichotoma |
Nassella cernua |
|
Distribution |
IL; KY; NC; SC |
CA; HI
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Discussion | Nassella trichotoma is a native of South America, and has been accidentally introduced into the United States. Because it is on the U.S. Department of Agriculture's noxious weed list, all known populations have been eliminated. New populations should be reported to the Department. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Nassella cernua grows in grasslands, chaparral, and juniper associations of the inner coast ranges of California and Baja California, Mexico. Small specimens resemble N. lepida, but have longer and thicker awns and fewer florets. Large specimens resemble N. pulchra, but have thinner awns with cernuous, rather than straight, terminal segments. It is superficially similar to Achnatherum eminens, but differs in its shorter ligules, strongly overlapping lemma margins, glabrous paleas, and geographic distribution. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 24, p. 177. | FNA vol. 24, p. 176. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Stipa cernua | |
Name authority | (Nees) Hack, ex Arechav. | (Stebbins & Love) Barkworth |
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