Piptochaetium fimbriatum
Piptochaetium avenacioides
pinon ricegrass, pinyon ricegrass
Florida speargrass
35-95 cm, usually glabrous, sometimes pubescent below the nodes;
nodes 2-3, often dark, glabrous.
70-130 cm, mostly glabrous, sometimes pubescent below the nodes;
nodes yellowish, 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;
ligules blunt to acute, of basal leaves 0.4-0.7 mm, of upper leaves to 3 mm;
blades 15-30 cm long, 0.8-1.5 mm wide, usually involute and 0.5 mm in diameter, 3-veined, abaxial surfaces usually glabrous and smooth, sometimes scabrous, adaxial surfaces usually scabrous over the veins, sometimes smooth, sometimes hairy.
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.
10-31 cm, open, with 10-50 spikelets;
pedicels 15-20 mm, scabrous.
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.
15-22 mm, (3)5-veined;
florets 13.5-22 mm long, 1-2 mm thick, terete;
calluses 3.5-8 mm, sharp, strigose, hairs golden brown at maturity;
lemmas glabrous, tan to brown at maturity, mostly smooth, sharply tuberculate distally, contracted below the crown;
crowns 0.6-0.7 mm wide, hairy, hairs 0.2-0.6 mm;
awns 62-120 mm, persistent, twice-geniculate;
paleas 9-12 mm;
lodicules 2;
anthers 4-7 mm.
2.5-3 mm long, about 0.6 mm thick, fusiform.
= 42.
= unknown.
Piptochaetium fimbriatum
Piptochaetium avenacioides
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 avenacioides grows in dry woods, generally on sandy ridges. It is endemic to Florida, growing primarily in the central peninsula. Morph-ologically, it is very similar to P. avenaceum, differing only in its larger size and more restricted distribution.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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