Achnatherum richardsonii
Achnatherum splendens
Richardson needlegrass, Richardson's needlegrass, Richardson's rice grass, spreading needlegrass
jiji grass
30-100 cm tall, 1-1.5 mm thick, glabrous;
nodes usually 3.
30-250 cm tall, 2-3 mm thick, glabrous, smooth;
nodes 1-3.
7-25 cm long, 7-15 cm wide;
branches divergent, flexuous, longest branches 7-10 cm, with the spikelets confined to the distal 1/4.
12-50 cm long, 4-15 cm wide;
branches ascending, usually whorled, longest branches 2.5-15 cm, with 15+ spikelets.
pendulous.
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.
7.5-11 mm long, 0.9-1.2 mm wide;
upper glumes 2-3 mm shorter;
florets 5-6 mm long, 0.6-0.9 mm thick, fusiform, terete;
calluses 0.4-0.7 mm, blunt;
lemmas evenly hairy on the lower portion, often glabrate distally, body and apical hairs 0.2-0.5 mm, apical lobes not or scarcely developed, to 0.1 mm;
awns 15-25 mm, persistent, twice-geniculate, first 2 segments strigulose, hairs about 0.1 mm, terminal segment straight;
paleas 2.2-3.6 mm, 1/2 - 3/5 as long as the lemmas, pubescent, hairs not exceeding the apices, apices rounded;
anthers 2.5-3 mm, dehiscent, penicillate, hairs 0.1-0.5 mm.
3-4 mm, fusiform.
2-4 mm, fusiform.
sheaths glabrous, margins ciliolate;
collars glabrous, without tufts of hair on the sides;
ligules 0.1-0.5 mm, truncate, ciliolate;
blades 0.8-3 mm wide, convolute when dry, abaxial surfaces scabridulous, adaxial surfaces glabrous.
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.
= 44.
=42, 48.
Achnatherum richardsonii
Achnatherum splendens
Achnatherum richardsonii grows in open woodlands and grasslands,often on sand or gravel, from the Yukon Territory to Washington and Manitoba, and south in the Rocky Mountains through Montana and Wyoming to western South Dakota and northern Colorado. Its elevation range is 1000-3100 m. It is readily recognized by its combination of flexuous panicle branches, drooping spikelets, and straight distal awn segments. Scagel and Maze (1984) concluded that putative hybrids between A. richardsonii and A. nelsonii subsp. dorei were merely large plants of subsp. dorei that varied in the direction of A. richardsonii.
(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.)
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