Achnatherum diegoense
Achnatherum perplexum
San Diego County needlegrass, San Diego needlegrass
New Mexico needlegrass, perplexing 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.
35-90 cm tall, 0.7-2.2 mm thick, lower internodes glabrous, puberulent to 5 mm below the nodes;
nodes 2-3.
21-25 cm long, (2)4-8 cm wide;
branches strongly divergent to ascending, straight, lower branches 5-7 cm.
10-25 cm long, 0.5-1.5 cm wide;
branches ascending to appressed, straight.
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.
unequal;
lower glumes 10-15 mm long, 0.5-1.1 mm wide, exceeding the upper glumes by 1-3(4) mm;
florets 5.5-11 mm long, 0.7-1 mm thick, fusiform, terete, widest at or below midlength;
calluses 0.4-0.6 mm, blunt;
lemmas evenly hairy, hairs at midlength about 1 mm, apical hairs 1-2 mm, ascending to divergent, apical lobes 0.2-0.5 mm, membranous, flexible;
awns 10-19 mm, persistent, once(twice)-geniculate, basal segments scabrous, terminal segments straight;
paleas 2.8-5.6 mm, 1/2 -2/3 as long as the lemmas, hairy, hairs not or scarcely exceeding the apices, veins terminating at or before the apices, apices acute to rounded;
anthers 2.5-4 mm, dehiscent, not penicillate.
3-6 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 mostly glabrous, margins ciliolate distally;
collars glabrous, including the sides;
basal ligules 0.2-0.5 mm, truncate, ciliolate, cilia to 0.1 mm;
upper ligules 0.2-3.5 mm, rounded to acute;
blades to 30 cm long, 1-3 mm wide.
= unknown.
= unknown.
Achnatherum diegoense
Achnatherum perplexum
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 perplexum grows on slopes in pinyon-pine associations of the southwestern United States and adjacent Mexico, at 1500-1700 m. It flowers in late summer to early fall. It has generally been confused with A. scribneri, A. nelsonii, and A. lobatum. It differs from A. scribneri in the glabrous collar margins of its basal leaves and its blunt calluses; from A. nelsonii and A. lettermanii in its unequal glumes; from A. lettermanii in its relatively short paleas; and from A. lobatum in its shorter lemma lobes and ascending to divergent apical lemma hairs.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
CA
WildflowerSearch
iNaturalist
USDA Plants Database
