Achnatherum robustum
Eriocoma hendersonii
(synonym of Achnatherum hendersonii)
Henderson's ricegrass
0.3–0.9 mm thick, pubescent below the nodes, glabrous or pubescent elsewhere.
basal sheaths glabrous or nearly so;
margins sometimes ciliate distally;
collars glabrous;
ligules 0.4–1 mm;
blades convolute; to 1 mm in diameter;
outer surface scabrous;
inner surface pubescent.
4–12 × 2–5 cm;
branches straight, appressed to ascending; longest branches 2–7 cm.
3.5–5.5 mm subequal, 1–1.5 mm wide, 5-veined, rounded to obtuse or acute;
upper glumes to 1 mm; shorter than lower glumes.
3.5–4.5 × 1–1.5 mm, laterally compressed.
0.3–0.6 mm; blunt.
leathery, glabrous; shiny, dark brown; apical lobes thick; about 0.2 mm;
lemma awns 6–10 mm, deciduous, not bent, scabrous.
75% to as long as the lemmas; hard; flat, glabrous.
1.4–2(2.5)mm, with a tuft of short hairs at the end.
Achnatherum robustum
Eriocoma hendersonii
[Originally published in Flora of Oregon as Achnatherum hendersonii.]
Shallow, rocky soil in scablands, sagebrush-steppe, or ponderosa pine forest, often in areas with frost heaving. 900– 1500m. Col. WA. Native.
This species has dark brown, shiny, more or less elliptic lemmas that are nearly visible through the translucent glumes. The lemma awns fall off early in development.
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
OR
WA
