Achnatherum diegoense
Achnatherum scribneri
San Diego County needlegrass, San Diego needlegrass
Scribner needlegrass, Scribner'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.
25-90 cm tall, 0.5-1.6 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.
7-21 cm long, 0.5-1 cm wide;
branches appressed to ascending, straight.
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.
10-17 mm long, 0.7-1.2 mm wide, exceeding the upper glumes by 2.5-4.5 mm, apices tapering, often slightly recurved;
florets 6-9.5 mm long, 0.6-1.1 mm thick, fusiform, terete, widest at or below midlength;
calluses 0.5-1.5 mm, sharp;
lemmas evenly hairy, hairs at midlength to 1 mm, apical hairs 2-3 mm, ascending, apical lobes 0.3-0.5 mm;
awns 13-25 mm, persistent, usually once-geniculate, first segment scabrous, terminal segment straight;
paleas 2.5-3.5 mm, 1/3 – 1/2 as long as the lemmas, pubescent, hairs not exceeding the apices, apices rounded;
anthers 3-5 mm, dehiscent, not penicillate.
5-6 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 becoming flat and papery, margins ciliate distally;
collars glabrous, with tufts of hair on the sides, hairs on the basal leaves to 1.5 mm, hairs on the flag leaves 1-2.5 mm;
basal ligules 0.3-0.8 mm, truncate, erose, ciliate, cilia 0.2-0.4 mm;
upper ligules to 1.5 mm, asymmetric, obliquely truncate for most of their width, abruptly longer on 1 side;
blades to 30 cm long, 2-5 mm wide, flat or involute, long-tapering.
= unknown.
= 40.
Achnatherum diegoense
Achnatherum scribneri
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 scribneri grows on rocky slopes, in pinyon-juniper and ponderosa pine associations at 1500-2700 m, from southeastern Wyoming through Colorado to Arizona, New Mexico, western Oklahoma, and Texas, and in Capital Reef National Park, Utah. At present, the Utah population appears to be disjunct from the species' primary range; this may reflect a lack of collecting. Achnatherum scribneri is similar to A. parishii, A. robustum, A. perplexum, and A. lobatum, differing from all of them in its sharp calluses.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
CA
WildflowerSearch
iNaturalist
USDA Plants Database
