Stipa acuta

HABIT Perennial; caespitose. Culms erect; slender; 95 cm long. Leaf-sheaths mostly shorter than adjacent culm internode; glabrous on surface. Ligule an eciliate membrane; 1.5–2 mm long; lacerate; acute. Leaf-blades involute; 10–23 cm long; 1–2 mm wide. Leaf-blade surface glabrous. Leaf-blade margins scabrous.

INFLORESCENCE Inflorescence a panicle.

Panicle open; elliptic; 15–20 cm long. Primary panicle branches ascending, or spreading; 3–6 cm long. Panicle branches flexuous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels 2–5 mm long.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; subterete; 11–12 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus elongated; 1 mm long; pubescent; pungent.

GLUMES Glumes persistent; similar; exceeding apex of florets; thinner than fertile lemma. Lower glume lanceolate; 11–12 mm long; 1.1–1.2 length of upper glume; hyaline; purple; without keels; 3 -veined. Lower glume lateral veins with cross-veins. Lower glume apex acute. Upper glume lanceolate; 9–10 mm long; hyaline; purple; without keels; 5–7 -veined. Upper glume lateral veins with cross-veins. Upper glume apex acute.

FLORETS Fertile lemma linear; subterete; 7 mm long; coriaceous; dark brown; without keel; 5 -veined. Lemma surface pubescent. Lemma margins convolute; covering most of palea. Lemma apex awned; 1 -awned. Principal lemma awn bigeniculate; 45–50 mm long overall; with 30–35 mm long limb; with twisted column.

DISTRIBUTION North America: Mexico.

NOTES Stipeae. Gr Swallen 2004.

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