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.

Aulonemia laxa

HABIT Perennial; caespitose. Rhizomes short; pachymorph. Culms erect; 100–120 cm long; 4–4.5 mm diam.; woody. Culm-internodes terete; hollow; 7.5–21 cm long. Lateral branches dendroid; erect. Bud complement 1. Branch complement one; solitary. Leaf-sheaths 7.5–10 cm long; glabrous on surface. Leaf-sheath oral hairs setose; 15–20 mm long. Ligule an eciliate membrane; 0.8–1 mm long. Collar with external ligule. Leaf-blade base with a brief petiole-like connection to sheath. Leaf-blades lanceolate, or oblong; 15–24.5 cm long; 42–48 mm wide. Leaf-blade venation with distinct cross veins. Leaf-blade margins scabrous. Leaf-blade apex attenuate.

INFLORESCENCE Inflorescence a panicle.

Panicle open; ovate; 30 cm long. Primary panicle branches 3–4 in number; ascending, or spreading, or drooping.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 4 fertile florets; with diminished florets at the apex. Spikelets linear; laterally compressed; 35–48 mm long; 3 mm wide; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 8 mm long.

GLUMES Glumes several; 3 empty glumes; persistent; similar; shorter than spikelet. Upper glume ovate; 13 mm long; membranous; without keels.

FLORETS Fertile lemma ovate; 17–20 mm long; chartaceous; without keel; 9 -veined. Lemma apex acute; awned; 1 -awned. Principal lemma awn 8.5–14.2 mm long overall. Palea 15 mm long. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 3; 2.8 mm long. Anthers 3; 10.5 mm long. Stigmas 2.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION North America: Mexico.

NOTES Bambuseae. Maekawa 1996.

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