Achnatherum robustum
Achnatherum splendens
sleepy grass
jiji grass
100-230 cm tall, 2-4.5 mm thick, mostly glabrous, often pubescent below the nodes, the pubescence antrorse or retrorse;
nodes 4-5.
30-250 cm tall, 2-3 mm thick, glabrous, smooth;
nodes 1-3.
15-30 cm long, 0.8-3.5 cm wide;
branches straight, appressed to ascending, lower branches 3-9 cm.
12-50 cm long, 4-15 cm wide;
branches ascending, usually whorled, longest branches 2.5-15 cm, with 15+ spikelets.
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.
4-8.5 mm, acute;
lower glumes 0-1.7 mm shorter than the upper glumes;
upper glumes 0.5-0.9 mm wide;
florets 4-7.2 mm, fusiform;
calluses 0.3-0.5 mm, blunt;
lemmas evenly hairy, hairs at midlength to 1 mm, apical hairs to 1.5 mm, apical lobes 0.5-1 mm;
awns 5-12 mm, readily deciduous, indistinctly once-geniculate or flexuous, scabrous;
paleas slightly shorter than the lemmas, pubescent;
anthers 3-4.5 mm, dehiscent, penicillate, yellow.
5-6 mm.
2-4 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 glabrous or the margins ciliate, becoming fibrous with age;
collars glabrous, including the sides;
basal ligules 1-3 mm, membranous, glabrous, truncate to acute;
upper ligules to 12 mm, acute;
blades to 60 cm long, 2-5 mm wide, abaxial surfaces smooth, adaxial surfaces scabrous.
= 64.
=42, 48.
Achnatherum robustum
Achnatherum splendens
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 splendens is native from the Caspian Sea to eastern Siberia and south through central Asia to the inner ranges of the Himalayas. According to Freitag (1985), it is a common and typical plant of cold, semidesert regions, growing in groundwater-influenced habitats at elevations of 2100-3800 m. It is rarely eaten by grazing animals, so that it increases in abundance in overgrazed meadows. It is being considered as a potential soil binder for areas in Asia that are too cold for Chrysopogon zizanioides (L.) Roberty A.S. Hitchcock (1951) reported A. splendens to be "sparingly cultivated" in the United States. In view of Freitag's comments, its cultivation in North America should be discouraged.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
KS Wildflowers
WildflowerSearch
iNaturalist
USDA Plants Database
