Achnatherum lemmonii

(Vasey) Barkworth
Common names: Lemmon's needlegrass
Endemic
Synonyms: Stipa lemmonii
Treatment appears in FNA Volume 24. Treatment on page 125.

Plants tightly cespitose, not rhizomatous. Culms 15-90 cm tall, 0.7-1 mm thick, glabrous, pubescent, or tomentose; nodes 3-4. Basal sheaths glabrous, pubescent, or tomentose; collars, including the sides, glabrous or sparsely pubescent, hairs shorter than 0.5 mm; basal ligules 0.5-1.2 mm, hyaline, glabrous, truncate to acute; upper ligules to 2.5 mm; basal blades 0.5-1.5 mm wide, folded to convolute, abaxial surfaces smooth, glabrous, adaxial surfaces prominently ribbed, often with 0.3-0.5 mm hairs, sometimes glabrous; upper blades to 2.5 mm wide, otherwise similar to the basal blades. Panicles 7-21 cm long, about 1 cm wide; branches straight, strongly ascending to appressed, longest branches 4-5 cm. Spikelets appressed to the branches. Glumes subequal, 7-11.5 mm; lower glumes 0.9-1.1 mm wide, 4-5-veined; upper glumes 3-veined; florets 5.5-7 mm long, 0.8-1.3 mm thick, fusiform, somewhat laterally compressed; calluses 0.4-1.2 mm, blunt; lemmas coriaceous, evenly pubescent, hairs 0.4-1 mm, apices 1-lobed, lobe about 0.1 mm long, thick, stiff, apical lemma hairs 0.4-0.8 mm; awns 16-30 mm, persistent, (once) twice-geniculate, all segments scab¬rous, terminal segment straight; paleas 4.5-6.5 mm, from 3/4 as long as to equaling the lemmas, sparsely to moderately pubescent, hairs not exceeding the apices, veins terminating below the apices, apices flat or pinched; anthers 2.3-3.5 mm, dehiscent, not penicillate. Caryopses 4-5 mm, fusiform. 2n = 34.

Distribution

Wash., B.C., Utah, Calif., Oreg., Mont., Ariz., Idaho, Nev.

Discussion

Achnatherum lemmonii grows in sagebrush and yellow pine associations, from southern British Columbia to California and east to Utah. It has been confused in the past with A. nelsonii; it differs in having narrower leaves, laterally compressed florets with a thick apical lobe, and longer paleas.

Selected References

None.

Key

1 Lower sheaths and culms glabrous or pubescent, not tomentose, the hairs to 0.2 mm long Achnatherum lemmonii subsp. lemmonii
1 Lower sheaths and culms tomentose, the hairs 0.4-0.6 mm long Achnatherum lemmonii subsp. pubescens

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

... more about "Achnatherum lemmonii"
membranous +  and scarious +
not penicillate +
0.23 cm2.3 mm <br />0.0023 m <br /> (0.35 cm3.5 mm <br />0.0035 m <br />) +
awned +, bifid +, bilobed +  and entire +
0 cm0 mm <br />0 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
Mary E. Barkworth +
(Vasey) Barkworth +
1 (?) +  and 3 (?) +
flexuous +
subterminal +  and eccentric +
usually scabrous +  and scabridulous +
not once-geniculate +
1.6 cm16 mm <br />0.016 m <br /> (3 cm30 mm <br />0.03 m <br />) +
keeled +  and rounded +
folded +  and convolute +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
tomentose +, pubescent +  and glabrous +
pseudopetiolate +  and branching +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
not evident +
involute +, convolute +  and flat +
strongly ascending;appressed +
spikelike +
well-developed +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.12 cm1.2 mm <br />0.0012 m <br />) +
pubescent +  and glabrous +
Lemmon's needlegrass +
branching +  and not branching +
perennial +  and annual +
15 cm150 mm <br />0.15 m <br /> (90 cm900 mm <br />0.9 m <br />) +
intravaginal +  and basal +
tomentose +, pubescent +  and glabrous +
10 cm100 mm <br />0.1 m <br /> (250 cm2,500 mm <br />2.5 m <br />) +
not woody +
0.07 cm0.7 mm <br />7.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
Wash. +, B.C. +, Utah +, Calif. +, Oreg. +, Mont. +, Ariz. +, Idaho +  and Nev. +
1/5 +  and 1/3 +
liquid +, soft +  and hard +
capillary +
pistillate +  and staminate +
0.55 cm5.5 mm <br />0.0055 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
sometimes longer +
compressed +  and fusiform +
1-10-veined +
subtending +
obtuse +, acute +  and acuminate +
subequal +
0.7 cm7 mm <br />0.007 m <br /> (1.15 cm11.5 mm <br />0.0115 m <br />) +
membranous +
divergent +  and distributed +
uncinate +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
solid +  and hollow +
basally concentrated +  and evenly distributed +
0 cm0 mm <br />0 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
ovate +, rectangular +  and lanceolate +
coriaceous +
pubescent +  and glabrous +
membranous +
0.1 cm1 mm <br />0.001 m <br /> (?) +
membranous +
inconspicuous +
not lobed +
4 cm40 mm <br />0.04 m <br /> (5 cm50 mm <br />0.05 m <br />) +
0.9mm +  and 1.1mm +
concealed +  and prominent +
3 +  and 4 +
2 +  and 1 +
pubescent +  and glabrous +
well-developed +
not keeled +
reduced +
0.45 cm4.5 mm <br />0.0045 m <br /> (0.65 cm6.5 mm <br />0.0065 m <br />) +
7cm +  and 21cm +
1 cm10 mm <br />0.01 m <br /> (?) +
dry +  and fleshy +
not prolonged +
1 +  and 60 +
unisexual +  and bisexual +
laterally compressed +  and terete +
1 (?) +  and 3 (?) +
simple +  and compound +
Stipa lemmonii +
Achnatherum lemmonii +
Achnatherum +
species +
membranous +
0 cm0 mm <br />0 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
inconspicuous +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
plant +  and cespitose +
aquatic +  and terrestrial +