Achnatherum diegoense
Achnatherum curvifolium
San Diego County needlegrass, San Diego needlegrass
curlyleaf needlegrass, Guadalupe ricegrass
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.
25-55 cm tall, 0.7-1 mm thick, glabrous;
nodes 3.
21-25 cm long, (2)4-8 cm wide;
branches strongly divergent to ascending, straight, lower branches 5-7 cm.
7-11 cm long, 1-2 cm wide;
branches appressed to strongly ascending, longest branches 3-4 cm.
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.
subequal, 10-14 mm long, 0.7-0.9 mm wide;
florets 6-8 mm long, 0.4-0.8 mm thick, fusiform, terete;
calluses 1-1.5 mm, sharp;
lemmas evenly hairy, hairs at midlength 0.3-1 mm, apical hairs 1-1.5 mm, apical lobes not developed;
awns 22-38 mm, once-geniculate, first segment pubescent, hairs 1-2 mm, gradually decreasing in length distally;
paleas 2-2.3 mm, 1/4-1/3 as long as the lemmas, glabrous;
anthers about 3.5 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 usually puberulent, hairs 0.1-0.2 mm, sometimes densely tomentose at the base, brown to gray-brown when old;
collars glabrous, sometimes with tufts of hair on the sides, hairs to 0.5 mm;
ligules truncate, pubescent, hairs about 0.1;
basal ligules about 0.3 mm, upper ligules to 0.6 mm;
blades normally valvate to involute, about 0.5 mm in diameter, strongly arcuate, abaxial surfaces pubescent near the base, glabrous and smooth distally, adaxial surfaces densely hairy, hairs to 0.2 mm.
= unknown.
= 44.
Achnatherum diegoense
Achnatherum curvifolium
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 curvifolium grows on cliffs and in disturbed, rocky, limestone habitats. It is known from relatively few locations in the Flora region; it is more common in northern Mexico. It is most readily distinguished from other species of Achnatherum in the Flora region by its combination of curly leaves and hairy awns.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
CA
WildflowerSearch
iNaturalist
USDA Plants Database
