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 dichotoma

HABIT Annual. Culms zigzag; 15–75 cm long; wiry. Lateral branches ample; arising from mid culm and upper culm. Leaf-sheaths without keel; glabrous on surface. Ligule a fringe of hairs; 0.2–0.3 mm long. Leaf-blades filiform; 8–15 cm long; 1–2 mm wide. Leaf-blade surface glabrous, or pilose; sparsely hairy.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; linear; 4–15 cm long.

Spikelets solitary. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets linear; subterete; 4–10 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus evident; 0.5 mm long; pubescent; obtuse.

GLUMES Glumes similar; reaching apex of florets, or exceeding apex of florets; thinner than fertile lemma. Lower glume lanceolate; 4–10 mm long; 1 length of upper glume; membranous; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute, or setaceously attenuate. Upper glume lanceolate; 4–10 mm long; 1–1.6 length of adjacent fertile lemma; membranous; 1 -veined. Upper glume lateral veins absent. Upper glume apex acute, or setaceously attenuate.

FLORETS Fertile lemma linear; subterete; 4–6 mm long; coriaceous; yellow and purple; mottled with last colour; without keel; 3 -veined. Lemma surface pubescent. Lemma margins convolute; covering most of palea. Lemma apex awned; 3 -awned. Principal lemma awn 3-branched; spreading and briefly coiled at base of limb; with 5–9 mm long limb; without a column. Lateral lemma awns spreading less than principal; 1–2 mm long; shorter than principal.

FLOWER Anthers 3.

DISTRIBUTION North America: eastern Canada, northwest USA, north-central USA, northeast USA, south-central USA, and southeast USA.

NOTES Aristideae. Gr Tex 1993.

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