Achnatherum lemmonii

(Vasey) Barkworth
Common names: Lemmon's needlegrass
Synonyms: Stipa lemmonii
Found 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.

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
Facts about "Achnatherum lemmonii"
AuthorMary E. Barkworth +
Common nameLemmon's needlegrass +
ReferenceNone +
SynonymStipa lemmonii +
Taxon nameAchnatherum lemmonii +
Taxon parentAchnatherum +
Taxon rankspecies +
VolumeVolume 24 +