Plants perennial; cespitose or soboliferous, sometimes rhizomatous. Culms 10-140 (150) cm, erect, usually glabrous, usually smooth; nodes 1-6; branching intra or extravaginal at the base, not branching above the base; prophylls concealed by the leaf-sheaths. Leaves sometimes basally concentrated; cleistogenes not present; sheaths open, glabrous, smooth to scabrous; auricles absent; ligules 0.2-15 mm, membranous to hyaline; blades 0.5-16 mm wide, flat, involute, valvate, or folded, often tapering in the distal 1/3, apices acute to acuminate, not stiff, basal blades not overwintering, sometimes not developed, flag leaf-blades well developed, longer than 1 cm. Inflorescences 3-40 cm, terminal panicles, open or contracted; branches straight or flexuous, usually scabrous, rarely smooth; pedicels often appressed to the branches. Spikelets 1.5-7.5 mm, with 1 floret; rachillas not prolonged beyond the floret; disarticulation above the glumes, beneath the floret. Glumes from 1 mm shorter than to exceeding the florets, subequal or the lower glumes longer than the upper glumes, membranous, 1-9-veined, veins evident, apices obtuse to acute or acuminate; florets 1.5-10 mm, usually dorsally compressed, sometimes terete; calluses 0.1-0.6 mm, glabrous or with hairs, blunt; lemmas 1.2-9 mm, smooth, coriaceous or stiffly membranous, tawny or light-brown to black at maturity, 3-7-veined, margins flat, separated and parallel for their whole length at maturity, apices not lobed or lobed, glabrous or hairy, hairs about 0.5 mm, not spreading, awned, lemma-awn junction evident; awns 1-18 (20) mm, centric, often caducous, almost straight to once or twice-geniculate, scabrous; paleas as long as or slightly longer than the lemmas, similar in texture and pubescence, 2 (3) -veined, not keeled over the veins, flat between the veins, veins terminating near the apices, apices often pinched; anthers 3, 0.6-5 mm, sometimes penicillate; styles 2 and free to their bases, or 1 with 2-3 branches. Caryopses glabrous, ovoid to obovoid; hila 1/2 as long as to equaling the length of the caryopses. x = 11, 12.

Distribution

Md., N.J., Utah, Calif., Pa., Ariz., Idaho, Nev.

Discussion

Piptatherum has approximately 30 species, most of which are Eurasian. They extend from lowland to alpine regions, and grow in habitats ranging from mesic forests to semideserts.

The pistils in Piptatherum exhibit variability in the development of the styles, a feature that can be seen only in florets shortly before or at anthesis. This variability is reported in the descriptions, but the number of specimens examined per species is low, sometimes only one.

Key

1 Basal leaf blades 0-2 cm long; cauline leaf blades 8-16 mm wide; florets 4.5-7.5 mm long Piptatherum racemosum
1 Basal leaf blades 4-45 cm long; cauline leaf blades 0.5-10 mm wide; florets 1.5-6 mm long. > 2
2 Lemmas and calluses usually glabrous, occasionally sparsely pubescent; florets 1.5-2.5 mm long. > 3
3 Blades 0.5-2.5 mm wide, often involute; panicles 5-20 cm long, the lower nodes with 1-3 branches Piptatherum micranthum
3 Blades 2-10 mm wide, flat; panicles 10-40 cm long, the lower nodes usually with 3-7 branches, sometimes with 15-30+ branches Piptatherum miliaceum
2 Lemmas evenly pubescent; calluses hairy; florets 1.5-6 mm long. > 3
4 Awns 3.9-15 mm long, persistent, once- or twice-geniculate. > 5
5 Primary panicle branches straight, appressed; awns 3.9-7 mm long; florets 3-6 mm long Piptatherum exiguum
5 Primary panicle branches somewhat flexuous, often divergent; awns 5-15 mm long; florets 2.2-4.5 mm long Piptatherum canadense
4 Awns 1-8 mm long, caducous, often absent from herbarium specimens, straight or arcuate. > 5
6 Awns 4-8 mm long; florets 1.5-2.5 mm long Piptatherum micranthum
6 Awns 1-2.5 mm long; florets 2.2-4.5 mm long. > 7
7 Lower panicle branches straight; ligules 0.5-2.5 mm long Piptatherum pungens
7 Lower panicle branches flexuous; ligules 1.8-5.5 mm long Piptatherum shoshoneanum

"decumbent" is not a number."prolonged" is not a number.

... more about "Piptatherum"
membranous +  and scarious +
penicillate +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
awned +, bifid +, bilobed +  and entire +
not stiff +
hairy +  and glabrous +
Mary E. Barkworth +
P. Beauv. +
twisted +  and not branched +
1 (?) +  and 3 (?) +
20 cm200 mm <br />0.2 m <br /> (?) +
straight +
subterminal +  and eccentric +
2 times-geniculate scabrous +
0.1 cm1 mm <br />0.001 m <br /> (1.8 cm18 mm <br />0.018 m <br />) +
keeled +  and rounded +
not branching +
extravaginal +
swelling +
not evident +
tapering +
0.5mm;16mm +
flexuous +  and straight +
spikelike +
well-developed +
with hairs +  and glabrous +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.06 cm0.6 mm <br />6.0e-4 m <br />) +
solid +  and hollow +
perennial +  and annual +
10 cm100 mm <br />0.1 m <br /> (140 cm1,400 mm <br />1.4 m <br />) +
not woody +
Md. +, N.J. +, Utah +, Calif. +, Pa. +, Ariz. +, Idaho +  and Nev. +
0 +  and 1/3 +
liquid +, soft +  and hard +
capillary +
pistillate +  and staminate +
sometimes longer +
terete +  and compressed +
1.5mm +  and 10mm +
1-10-veined +
subtending +
narrowly lanceolate +  and ovate +
subequal +
membranous +
not spreading +
uncinate +
0.5 cm5 mm <br />0.005 m <br /> (?) +
3 cm30 mm <br />0.03 m <br /> (40 cm400 mm <br />0.4 m <br />) +
solid +  and hollow +
basally concentrated +  and evenly distributed +
light-brown +  and black +
ovate +, rectangular +  and lanceolate +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
membranous +  and coriaceous +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
membranous +
inconspicuous +
lanceolate +
fleshy +  and membranous +
concealed +  and prominent +
1 +  and 6 +
2 +  and 1 +
pubescent +  and glabrous +
well-developed +
2(3)-veined +
not keeled +
reduced +
dry +  and fleshy +
not prolonged +
curto1998a +, freitag1975a +, jacobs2006a +  and johnson1945a +
smooth to scabrous +
1 +  and 60 +
unisexual +  and bisexual +
laterally compressed +  and terete +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.75 cm7.5 mm <br />0.0075 m <br />) +
1 (?) +  and 3 (?) +
simple +  and compound +
2 (?) +  and 3 (?) +
Gramineae +
Piptatherum +
Poaceae tribe Stipeae +
membranous +
rhizomatous +  and soboliferous +
plant +  and cespitose +
aquatic +  and terrestrial +