Achnatherum diegoense
Achnatherum lettermanii
San Diego County needlegrass, San Diego needlegrass
Letterman needlegrass, Letterman's needlegrass
110-140 cm tall, 2.5-4 mm thick, internodes densely and retrorsely pubescent for 3-9 mm below the nodes, particularly the lower nodes, glabrous or retrorsely puberulent elsewhere;
nodes 3, pubescent or glabrate.
15-90 cm tall, 0.5-0.8 mm thick, usually glabrous, sometimes puberulent to 5 mm below the lower nodes;
nodes 2-3.
21-25 cm long, (2)4-8 cm wide;
branches strongly divergent to ascending, straight, lower branches 5-7 cm.
7-19 cm long, 0.5-1 cm wide;
branches straight, appressed to strongly ascending, longest branches 1.2-2.5 cm.
appressed to the branches.
appressed to the branches.
subequal, 8-11.5 mm;
lower glumes 0.5-1 mm wide, 3-5-veined;
upper glumes 3-veined;
florets 5.5-7.5 mm long, 0.7-1 mm thick, fusiform, terete;
calluses 0.25-1.2 mm, acute;
lemmas evenly hairy, hairs at midlength and at the apices 0.5-1 mm, apical lobes 0.2-0.4 mm, membranous, flexible;
awns 20-50 mm, persistent, twice-geniculate, all segments scabrous to scabridulous, terminal segment straight;
paleas 2.6-3.8 mm, 1/2 - 3/4 as long as the lemmas, pubescent, hairs not extending beyond the apices, veins terminating below the apices, apices rounded;
anthers 2.5-4 mm, dehiscent, not penicillate.
6.5-9 mm, subequal;
lower glumes 1(3)-veined;
upper glumes to 0.5 mm shorter than the lower glumes, 0.6-1 mm wide, 1-veined;
florets 4.5-6 mm long, 0.8-1 mm thick, fusiform, teret, widest below midlength;
calluses 0.4-1 mm, blunt;
lemmas evenly hairy, hairs at midlength about 0.5 mm, apical hairs 0.7-1.5(2) mm, apical lobes 0.3-0.8, membranous, flexible;
awns 12-25 mm, persistent, twice-geniculate, scabrous, terminal segment straight;
paleas 3-4 mm, 3/4 - 4/5(9/10) as long as the lemmas, veins terminating at or before the apices, apices round, flat, apical hairs 0.5-1 mm, extending beyond the palea body;
anthers 1.5-2 mm, dehiscent, not penicillate.
about 4 mm, fusiform.
sheaths mostly glabrous or puberulent, margins ciliate distally;
collars glabrous or with hairs, hairs mostly to 0.5 mm, sides with tufts of 1.5-2 mm hairs;
ligules 0.4-2 mm, rounded to acute, abaxial surfaces hairy, hairs to 0.5 mm;
upper ligules 1-3 mm, similar in structure and pubescence;
blades 1-3.5 mm wide, abaxial surfaces smooth or scabrous, adaxial surfaces prominently ribbed, hairy, hairs 2-3 mm.
sheaths smooth, glabrous, margins not ciliate;
collars, including the sides, glabrous or sparsely pubescent, collars of the flag leaves glabrous;
ligules 0.2-1.5(2) mm, without tufts of hair on the sides, truncate to rounded;
blades 0.5-2, wide, abaxial surfaces smooth to scabridulous, adaxial surfaces scabrous or puberulent.
= unknown.
= 32.
Achnatherum diegoense
Achnatherum lettermanii
Achnatherum diegoense grows in chaparral and coastal sage scrub, on rocky soil near streams or the coast, at 0-350 m, on the Channel Islands of Santa Barbara County, California, and, on the mainland, in Ventura and San Diego counties south into Baja California, Mexico.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Achnatherum lettermanii grows in meadows and on dry slopes, from sagebrush to subalpine habitats, at 1700-3400 m. Its range extends from Oregon and Montana to southern California, Arizona, and New Mexico; it is not known from Mexico. When sympatric with A. nelsonii, A. lettermanii tends to grow in shallower or more disturbed soils. It can be distinguished from that species by its generally finer leaves and more tightly cespitose growth habit, as well as its blunter calluses and longer paleas. Its relatively long paleas also distinguish A. lettermanii from A. perplexum.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
CA
WildflowerSearch
iNaturalist
USDA Plants Database
Flora NW
PNW Herbaria
