Achnatherum robustum
Achnatherum parishii
sleepy grass
Parish's needlegrass
100-230 cm tall, 2-4.5 mm thick, mostly glabrous, often pubescent below the nodes, the pubescence antrorse or retrorse;
nodes 4-5.
14-80 cm tall, 0.8-2 mm thick, internodes glabrous or pubescent below the nodes;
nodes 3-5, glabrous.
15-30 cm long, 0.8-3.5 cm wide;
branches straight, appressed to ascending, lower branches 3-9 cm.
7-15 cm long, 1.5-4 cm wide;
branches strongly ascending at maturity, longest branches 1.5-4 cm.
appressed to the branches.
subequal, 9-11.5 mm long, 1-1.4 mm wide;
florets 5.9-8.5 mm long, 0.9-1.2 mm thick, fusiform, terete;
calluses 0.3-1 mm, blunt;
lemmas evenly hairy, hairs at midlength 0.3-0.8 mm, apical hairs to 1.5 mm;
awns 20-32 mm, persistent, twice-geniculate, scabridulous to scabrous, scabrules to about 0.1 mm, longest on the middle segment, terminal segment straight;
paleas 3.7-5.6 mm, 2/3 - 3/4 as long as the lemmas, hairy, hairs about 0.5 mm, not exceeding the apices, veins terminating below the apices, apices rounded;
anthers 4-5 mm, dehiscent, penicillate.
unequal to subequal, narrowly lanceolate, 3-5-veined;
lower glumes 9-15 mm long, 0.9-1.2 mm wide;
upper glumes 8-15 mm;
florets 4.8-6.5 mm long, 0.8-1 mm thick, fusiform, terete;
calluses 0.2-0.8 mm, acute;
lemmas evenly and densely hairy, hairs 1.5-3.5 mm at midlength, apical hairs 2.5-5 mm;
awns 10-35 mm, persistent, once-geniculate, first segment scabrous or strigose, hairs to 0.3 mm, terminal segment straight;
paleas 2.5-4.5 mm, 1/2 - 4/5 times the length of the lemmas, hairy between the veins, hairs often as long as those on the lemmas but not as dense, apices usually rounded, occasionally somewhat pinched;
anthers 2.3-4.5 mm, dehiscent, not penicillate.
5-6 mm.
3-6 mm, fusiform.
sheaths mostly glabrous, margins usually ciliate distaily;
collars hairy, those of the flag leaves densely hairy, hairs 0.5-2 mm, sides glabrous;
basal ligules 1-2 mm;
upper ligules to 4 mm, truncate, rounded, or obtuse, glabrous;
blades 6-10 mm wide, glabrous, abaxial surfaces smooth, adaxial surfaces prominently ribbed, ribs scabrous.
sheaths mostly glabrous, sometimes pubescent at the base, flat and ribbonlike with age, margins sometimes hairy distally, hairs adjacent to the ligules 0.5-3 mm;
collars glabrous;
ligules truncate, abaxial surfaces pubescent, ciliate, cilia as long as or longer than the basal membrane, ligules of basal leaves 0.3-0.8 mm, of upper leaves 0.5-1.5 mm, asymmetric;
blades 4-30+ cm long, 1-4.2 mm wide, usually flat and more or less straight, sometimes tightly convolute and arcuate.
= 64.
= unknown.
Achnatherum robustum
Achnatherum parishii
Achnatherum robustum grows on dry plains and hills, in open woods and forest clearings, and along roadsides, from Wyoming through Colorado to Arizona, New Mexico, and northern Mexico. Records from Kansas represent recent introductions; it is not clear whether the species has persisted there. Achnatherum robustum is sometimes confused with A. nelsonii subsp. dorei and Nassella viridula; it differs from both in the densely hairy collars of its flag leaves. Although not widely available, it has potential as an ornamental grass, particularly in arid regions with cold winters.
The English-language name refers to the effect some samples, particularly those from the Sacramento and Sierra Blanca mountains, New Mexico, have on livestock, especially horses and cattle. "Mildly poisoned animals are dejected, inactive, and withdrawn; severely poisoned animals lie on their sides in a profound slumber" (Cheeke and Shull 1985). The active ingredient is diacetone alcohol (Epstein et al 1964).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Achnatherum parishii grows from the coastal ranges of California to Nevada and Utah, south to Baja California, Mexico, and to the Grand Canyon in Arizona. It differs from A. coronatum in its once-geniculate awns, more densely pubescent paleas, and generally smaller stature; from A. scribneri in its shorter, blunter calluses and more abundant lemma hairs; and from A. perplexum in having longer hairs on its lemmas.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Basal sheath margins glabrous or hairy distaily, hairs to 0.5 mm long; culms 14-35 cm tall | subsp. depauperatum |
1. Basal sheath margins hairy distaily, hairs 1-3.2 mm long; culms 20-80 cm tall | subsp. parishii |
KS Wildflowers
WildflowerSearch
iNaturalist
USDA Plants Database
CalFlora
