Stipa robusta

HABIT Perennial; caespitose. Culms erect; robust; 100–150 cm long; 3–6 mm diam. Culm-internodes distally glabrous. Leaf-sheaths glabrous on surface; outer margin hairy. Leaf-sheath oral hairs ciliate. Ligule an eciliate membrane; 0.5–4 mm long. Collar pubescent. Leaf-blades flat, or involute; 30–50 cm long; 5–8 mm wide.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; linear; 25–50 cm long; 1–2 cm wide.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; subterete; 8–13 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus evident; 1 mm long; pubescent; unequally 2-toothed.

GLUMES Glumes persistent; similar; exceeding apex of florets; thinner than fertile lemma. Lower glume lanceolate; 8–13 mm long; 1 length of upper glume; hyaline; without keels; 3–5 -veined. Lower glume apex attenuate. Upper glume lanceolate; 8–13 mm long; 1.3–1.6 length of adjacent fertile lemma; hyaline; without keels; 3–5 -veined. Upper glume apex attenuate.

FLORETS Fertile lemma linear; subterete; 6–8 mm long; membranous; without keel; 5 -veined. Lemma surface tuberculate; pilose. Lemma margins flat; covering most of palea. Lemma hairs 1–2 mm long. Lemma apex awned; 1 -awned. Principal lemma awn bigeniculate; 20–38 mm long overall; with 12–18 mm long limb; with twisted column. Column of lemma awn glabrous, or puberulous. Palea 0.75 length of lemma; 2 -veined; without keels.

FLOWER Lodicules 3. Anthers 3; anther tip penicillate. Stigmas 2. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp. Hilum linear.

DISTRIBUTION North America: northwest USA, southwest USA, south-central USA, and Mexico.

NOTES Stipeae. Gr Texas 1994.

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