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.

Aristida spanospicula

HABIT Perennial; caespitose. Culms geniculately ascending; 20–60 cm long. Culm-internodes terete; smooth, or scaberulous; distally glabrous. Lateral branches lacking. Leaves mostly basal. Leaf-sheaths longer than adjacent culm internode; without keel; glabrous on surface, or pilose. Ligule a fringe of hairs; 0.3–0.5 mm long. Leaf-blades flat, or conduplicate; 14–25 cm long; 1.5–2 mm wide. Leaf-blade surface glabrous, or puberulous; hairy adaxially. Leaf-blade margins cartilaginous.

INFLORESCENCE Inflorescence a panicle; comprising 3–12 fertile spikelets.

Panicle open; oblong; equilateral, or nodding; 8–22 cm long; 1–2 cm wide; bearing few spikelets. Primary panicle branches ascending; bearing 1–2(–4) fertile spikelets on each lower branch.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets linear; subterete; 16–25 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus evident; 0.5–1 mm long; pubescent.

GLUMES Glumes similar; exceeding apex of florets; thinner than fertile lemma. Lower glume lanceolate; 9–15 mm long; 1 length of upper glume; membranous; light brown; 1 -veined. Lower glume lateral veins absent. Upper glume lanceolate; 9–15 mm long; 1–1.5 length of adjacent fertile lemma; membranous; light brown; 1 -veined. Upper glume lateral veins absent. Upper glume apex acuminate.

FLORETS Fertile lemma linear; subterete; 10 mm long; coriaceous; without keel; 3 -veined. Lemma surface glabrous. Lemma margins convolute; covering most of palea. Lemma apex awned; 1 -awned. Principal lemma awn geniculate; with 10–20 mm long limb; with twisted column. Column of lemma awn 6–15 mm long. Palea 1 mm long; hyaline; 2-keeled.

FLOWER Lodicules 2; 1–1.5 mm long. Anthers 3; 2 mm long; brown.

FRUIT Caryopsis with adherent pericarp; fusiform; 7–9 mm long.

DISTRIBUTION North America: Mexico.

NOTES Aristideae. Allred et al 2004.

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