Piptochaetium fimbriatum
Piptochaetium setosum
pinon ricegrass, pinyon ricegrass
bristly ricegrass, bristly speargrass
35-95 cm, usually glabrous, sometimes pubescent below the nodes;
nodes 2-3, often dark, glabrous.
20-40 cm, prostrate to ascending;
nodes 2, dark, glabrous.
glabrous, smooth;
ligules truncate to rounded, of basal leaves 0.4-1.8 mm, of upper leaves 1.5-2 mm;
blades 6-26 cm long, usually involute and 0.3-5 mm in diameter, sometimes flat and 0.5-1(1.5) mm wide, 3-veined, both surfaces glabrous, veins often scabridulous, margins scabrous.
glabrous, smooth;
ligules 0.5-2.5 mm, obtuse, membranous, glabrous;
blades (3)5-12.5 cm long, 0.8-1.5 mm wide, glabrous or hispidulous, margins scabridulous.
6.5-25 cm, open, often partially enclosed in the upper leaf sheath, with 20-60 spikelets;
branches flexuous;
pedicels 4-12 mm, flattened, hispid.
3-15 cm long, 2-3 cm wide, with (5)10-30 spikelets;
branches appressed to ascending, glabrous or hispid;
pedicels 2-6 mm, hispidulous.
subequal, 4-6.2 mm long, 1.8-3.1 mm wide, 5-7-veined, often partly purplish;
florets 3-5.5 mm long, 0.6-1.9 mm thick, somewhat laterally compressed, rectangular to slightly obovate in side view;
calluses 0.2-0.7 mm, blunt, strigose;
lemmas tan to light chocolate brown, shiny, smooth, evenly pubescent when immature, hairs easily rubbed off;
crowns about 0.8 mm wide, inconspicuous, glabrous or glabrate;
awns 11-20 mm, persistent, twice-geniculate;
paleas about 3.5 mm;
lodicules 2, about 1 mm;
anthers 0.3-0.5 mm, not penicillate.
subequal, 5-7 mm long, 1-2 mm wide, purplish at the base;
lower glumes (3)5(7)-veined;
upper glumes 5(7)-veined;
florets 2.5-3 mm long, 1.2-1.8 mm thick, globose to slightly laterally compressed, gibbous;
calluses 0.2-0.5 mm, obtuse, antrorsely strigose, hairs whitish to golden;
lemmas glabrous, longitudinally striate, constricted below the crown, chestnut brown at maturity;
crowns 0.5-0.8 mm wide, straight, not strongly differentiated, distal margins papillose;
awns 10-16 mm, once- or twice-geniculate;
paleas to 3.2 mm;
anthers about 0.5 mm.
2.5-3 mm long, about 0.6 mm thick, fusiform.
2-2.5 mm, spherical to ellipsoid.
= 42.
= unknown.
Piptochaetium fimbriatum
Piptochaetium setosum
Piptochaetium fimbriatum is an attractive species that grows in oak and pinyon woods of the southwestern United States and adjacent Mexico, and merits consideration as an ornamental. It has also been reported from Guatemala; the report has not been verified.
Piptochaetium fimbriatum is not easily confused with other species in our range. Hitchcock (1951) treated it as including P. seleri (Pilg.) Henrard, a Mexican species with dull, rough, oblanceolate lemmas and persistent lemma hairs, an interpretation that is no longer accepted. It is occasionally confused with P. pringlei; it differs from that species in having shorter florets and blunt calluses.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Piptochaetium setosum is native to central Chile. There is an established population in Marin County, California, that grows intermingled with P. stipoides, another South American species. The two species grow in the middle of a dirt track and in the adjacent meadow. The California plants of P. setosum are notable for their prostrate culms. This characteristic was not mentioned by Parodi (1944) or Cialdella and Arriaga (1998).
The origin of the California population is not known. It has been suggested that the seeds might have been brought in by birds, as the area was a bird refuge at one time.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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