GrassBase - The Online World Grass Flora

Descriptions

W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Aristida caput-medusae

HABIT Perennial; caespitose. Culms 33–85 cm long. Culm-internodes smooth, or scaberulous; distally glabrous. Culm-nodes glabrous. Lateral branches ample. Leaf-sheaths smooth, or scaberulous; glabrous on surface. Leaf-sheath oral hairs lacking, or ciliate; 0.5–2.5 mm long. Ligule a fringe of hairs; 0.5 mm long. Leaf-blades involute; 2–4 cm long; 0.5–1 mm wide. Leaf-blade surface scabrous; rough adaxially, or on both sides.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; lanceolate, or ovate; 3.9–8 cm long; 1–5 cm wide. Primary panicle branches 4–8 cm long; bearing spikelets almost to the base. Panicle branches scaberulous, or scabrous; with prominent pulvini.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; subterete; 6–9.5 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus elongated; 0.8–1.1 mm long; pubescent; acute.

GLUMES Glumes persistent; similar; shorter than spikelet; thinner than fertile lemma. Lower glume lanceolate; 2.7–5 mm long; 0.66 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume surface asperulous, or scabrous. Lower glume apex obtuse to acuminate. Upper glume lanceolate; 4–8 mm long; 0.66–0.8 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume lateral veins absent. Upper glume surface smooth to scabrous. Upper glume apex obtuse to acuminate.

FLORETS Fertile lemma lanceolate; subterete; 6–9.5 mm long; coriaceous; pallid, or light brown; concolorous, or mottled with last colour; without keel; 3 -veined. Lemma surface smooth, or scabrous; rough generally. Lemma margins convolute; covering most of palea. Lemma apex acute; awned; 3 -awned. Principal lemma awn spreading; flat below; with 7–13 mm long limb; without a column; persistent. Lateral lemma awns spreading as much as principal; 6–12 mm long; subequal to principal. Palea 0.2 length of lemma; without keels.

FLOWER Anthers 3; 1.3 mm long.

FRUIT Caryopsis with adherent pericarp; 4–6.1 mm long. Hilum linear; 0.4 length of caryopsis.

DISTRIBUTION Australasia: Australia.

NOTES Aristideae. Simon 1993.

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