Stipa alta

HABIT Perennial; caespitose; clumped densely. Culms erect; robust; 180 cm long. Culm-internodes distally glabrous. Leaves basal and cauline. Leaf-sheaths mostly shorter than adjacent culm internode; smooth, or scaberulous; glabrous on surface. Ligule an eciliate membrane; 4–8 mm long. Leaf-blades filiform; flat, or involute; 30–60 cm long; 3–7 mm wide; stiff. Leaf-blade surface scabrous. Leaf-blade margins scabrous. Leaf-blade apex attenuate; antrorsely scabrous.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; linear; 28 cm long; 1.5 cm wide; bearing few spikelets. Primary panicle branches appressed; 5–10 cm long; bearing 10–11 fertile spikelets on each lower branch.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; subterete; breaking up at maturity; disarticulating below each fertile floret. Spikelet callus pubescent; base acute. Floret callus brief; pubescent; acute.

GLUMES Glumes persistent; similar; subequal in width; exceeding apex of florets; thinner than fertile lemma. Lower glume lanceolate; 10–11 mm long; 1 length of upper glume; hyaline; 3 -veined. Lower glume apex acuminate. Upper glume lanceolate; 7–8 mm long; hyaline; without keels; 3 -veined. Upper glume apex setaceously attenuate.

FLORETS Fertile lemma linear to lanceolate; subterete; 4–5 mm long; coriaceous; dark brown; without keel. Lemma surface pilose. Lemma margins convolute; covering most of palea. Lemma apex awned; 1–2 -awned. Principal lemma awn geniculate; 8–12 mm long overall; with twisted column. Palea 2 -veined; without keels.

FLOWER Stigmas 2. Styles free to the base. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION North America: Mexico.

NOTES Stipeae. Swallen.

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