Stipa arida

HABIT Perennial; caespitose. Culms erect; 40–85 cm long. Culm-internodes distally glabrous. Culm-nodes glabrous, or pubescent. Leaf-sheaths smooth, or scaberulous; glabrous on surface. Leaf-sheath oral hairs pubescent. Ligule an eciliate membrane; 0.5–1 mm long. Leaf-blades flat, or involute; 15–25 cm long; 1–2.5 mm wide. Leaf-blade apex hardened.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; linear; 8–15 cm long. Primary panicle branches appressed.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; subterete; 9–15 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus elongated; curved; 1.5 mm long; pubescent; pungent.

GLUMES Glumes persistent; similar; with lower wider than upper; exceeding apex of florets; thinner than fertile lemma. Lower glume lanceolate; 9–15 mm long; 1.2–1.3 length of upper glume; hyaline; much thinner above; without keels; 3–5 -veined. Lower glume apex acuminate. Upper glume lanceolate; 7–12 mm long; 1.7–2 length of adjacent fertile lemma; hyaline; much thinner above; without keels; 3–5 -veined. Upper glume apex acuminate.

FLORETS Fertile lemma linear; subterete; 4–6 mm long; membranous; pallid; without keel; 5 -veined. Lemma surface asperulous; rough above; pubescent; hairy all along, or below. Lemma margins convolute; covering most of palea. Lemma apex with an annular corona; awned; 1 -awned. Principal lemma awn bigeniculate; 40–70 mm long overall; with 30–50 mm long limb; with twisted column. Column of lemma awn 10–20 mm long. Palea 0.4 length of lemma; 2 -veined; without keels.

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

FRUIT Caryopsis with adherent pericarp. Hilum linear.

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

NOTES Stipeae. Gr Texas 1994.

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