Hesperostipa

(M.K. Elias) Barkworth
Treatment appears in FNA Volume 24. Treatment on page 157.

Plants perennial; cespitose, not rhizomatous. Culms 12-110 cm, erect, not branching at the upper nodes; prophylls shorter than the sheaths. Leaves not overwintering, not basally concentrated; cleistogenes not developed; sheaths smooth; auricles absent; ligules membranous, frequently ciliate; blades 4-40 cm long, 0.5-4.5 mm wide, usually tightly involute, adaxial surfaces conspicuously ridged, apices narrowly acute, not sharp. Inflorescences terminal panicles, contracted or open. Spikelets 15-60 mm, with 1 floret; rachillas not prolonged beyond the base of the floret; disarticulation above the glumes and beneath the floret. Glumes 15-60 mm long, 2-4 mm wide, tapering from near the base to a hairlike tip; florets 7-25 mm, narrowly cylindrical; calluses 2-6 mm, sharp, densely strigose distally; lemmas indurate, smooth, margins flat, slightly overlapping at maturity, the upper portion fused into a papillose, ciliate crown, awned, lemma-awn junction distinct; awns 50-225 mm, persistent, twice-geniculate, often weakly so, lower segments twisted and scabrous to pilose, terminal segment not twisted, usually scabridulous or pilose; paleas equal to the lemmas, flat, pubescent, coriaceous, 2-veined, veins terminating at the apices, apices indurate, prow-tipped; anthers 3, 1.2-9 mm. Caryopses fusiform, not ribbed, x = 11.

Distribution

Wash., Wis., Wyo., N.Mex., Tex., Ill., Ind., Kans., N.Dak., N.Y., Okla., R.I., S.Dak., Pa., Nev., Colo., Calif., Nebr., Mont., Oreg., Iowa, Ariz., Idaho, Alta., B.C., Man., N.W.T., Ont., Sask., Yukon, Ohio, Utah, Mo., Minn., Mich.

Discussion

Hesperostipa is a North American endemic that resembles the Eurasian Stipa sensu stricto in overall morphology, but is more closely related to the primarily South American genera Piptochaetium and Nassella. It differs from Stipa sensu stricto in its indurate palea apices and its lemma epidermal patterns. There are five species in the genus, four of which are found in the Flora region. The fifth species, from southern Mexico, is known only from the type specimen.

Key

1 Awns pilose on all segments, the terminal segment with hairs 1-3 mm long Hesperostipa neomexicana
1 Awns scabrous to strigose on the first 2 segments, the terminal segment scabridulous. > 2
2 Lemmas usually evenly white-pubescent, sometimes glabrous immediately above the callus; lower ligules often lacerate Hesperostipa comata
2 Lemmas unevenly pubescent with brown to beige hairs; lower ligules not lacerate. > 3
3 Florets 8.5-14(17) mm long; awns 50-105 mm long; lower nodes usually glabrous, occasionally evenly pubescent Hesperostipa curtiseta
3 Florets 15-25 mm long; awns 90-190 mm long; lower nodes usually with lines of pubescence Hesperostipa spartea

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

... more about "Hesperostipa"
membranous +  and scarious +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
prow-tipped +
awned +, bifid +, bilobed +  and entire +
Not sharp (?) +  and Acute (?) +
indurate +
Mary E. Barkworth +
(M.K. Elias) Barkworth +
twisted +  and not branched +
1 (?) +  and 3 (?) +
subterminal +  and eccentric +
scabrous +  and pilose +
5 cm50 mm <br />0.05 m <br /> (22.5 cm225 mm <br />0.225 m <br />) +
keeled +  and rounded +
pseudopetiolate +  and branching +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
4 cm40 mm <br />0.04 m <br /> (40 cm400 mm <br />0.4 m <br />) +
not evident +
cross +, linear +  and narrowly lanceolate +
0.5mm;4.5mm +
spikelike +
well-developed +
0.2 cm2 mm <br />0.002 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
not branching +
perennial +  and annual +
12 cm120 mm <br />0.12 m <br /> (110 cm1,100 mm <br />1.1 m <br />) +
not woody +
Wash. +, Wis. +, Wyo. +, N.Mex. +, Tex. +, Ill. +, Ind. +, Kans. +, N.Dak. +, N.Y. +, Okla. +, R.I. +, S.Dak. +, Pa. +, Nev. +, Colo. +, Calif. +, Nebr. +, Mont. +, Oreg. +, Iowa +, Ariz. +, Idaho +, Alta. +, B.C. +, Man. +, N.W.T. +, Ont. +, Sask. +, Yukon +, Ohio +, Utah +, Mo. +, Minn. +  and Mich. +
0 +  and 1/3 +
liquid +, soft +  and hard +
capillary +
pistillate +  and staminate +
sometimes longer +
cylindrical +
7mm +  and 25mm +
15mm +  and 60mm +
subtending +
tapering +
membranous +
2mm +  and 4mm +
uncinate +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
solid +  and hollow +
basally concentrated +  and evenly distributed +
ovate +, rectangular +  and lanceolate +
membranous +
inconspicuous +
lanceolate +
fleshy +  and membranous +
concealed +  and prominent +
2 +  and 1 +
pubescent +  and glabrous +
well-developed +
reduced +
coriaceous +
dry +  and fleshy +
not prolonged +
barkworth1977a +, barkworth1987a +, elias1942a +, misra1961a +, misra1963a +  and thomasson1979a +
1 +  and 60 +
unisexual +  and bisexual +
laterally compressed +  and terete +
1.5 cm15 mm <br />0.015 m <br /> (6 cm60 mm <br />0.06 m <br />) +
1 (?) +  and 3 (?) +
simple +  and compound +
2 (?) +  and 3 (?) +
Gramineae +
Hesperostipa +
Poaceae tribe Stipeae +
membranous +
inconspicuous +
plant +  and cespitose +
aquatic +  and terrestrial +