GrassBase - The Online World Grass Flora


W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Stipa shoshoneana

HABIT Perennial; caespitose; clumped densely. Basal innovations intravaginal. Culms erect, or geniculately ascending; 20–50 cm long; 2–3 -noded. Culm-internodes scaberulous. Lateral branches lacking. Leaf-sheaths scaberulous. Ligule an eciliate membrane; 1.8–5.5 mm long; entire, or lacerate; acute. Leaf-blades flat, or involute; 5–20 cm long; 1–1.5 mm wide; stiff. Leaf-blade surface scaberulous.

INFLORESCENCE Inflorescence a panicle; without bracts, or bracteate at branch bases.

Panicle open; ovate; effuse; 3.3–22 cm long; with spikelets clustered towards branch tips. Primary panicle branches reflexed; 1–2(–4) -nate; 1.8–11.6 cm long. Panicle branches capillary; with prominent pulvini.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets elliptic; subterete; 3.3–5.3 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus brief; 0.3 mm long; glabrous; obtuse.

GLUMES Glumes persistent; similar; exceeding apex of florets; thinner than fertile lemma. Lower glume lanceolate; 3.2–5.1 mm long; 1 length of upper glume; membranous; without keels. Lower glume apex acute, or acuminate. Upper glume ovate; 3.3–5.3 mm long; 1.5 length of adjacent fertile lemma; membranous; without keels. Upper glume apex acute, or acuminate.

FLORETS Fertile lemma elliptic; dorsally compressed; 2.2–3.8 mm long; membranous; without keel; 5–7 -veined. Lemma surface pubescent. Lemma margins flat; covering most of palea. Lemma hairs tawny. Lemma apex emarginate; awned; 1 -awned. Principal lemma awn straight; 1–2.5 mm long overall; deciduous. Palea 2.1–3.6 mm long; 1 length of lemma; 2 -veined; without keels.

FLOWER Lodicules 3; 0.75–1.25 mm long. Anthers 3; 1.75–2.2 mm long; yellow; anther tip smooth. Stigmas 2.

FRUIT Caryopsis with adherent pericarp; obovoid; dorsally compressed; 2 mm long. Hilum linear; 0.9 length of caryopsis.

DISTRIBUTION North America: northwest USA.

NOTES Stipeae. Curto & Henderson 2004.

Please cite this publication as detailed in How to Cite Version: 3rd February 2016.