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 thompsonii

HABIT Perennial; caespitose. Culms erect; 20–40 cm long; 1–1.5 mm diam.; 3–4 -noded. Culm-internodes glaucous; smooth; distally glabrous. Culm-nodes glabrous. Lateral branches sparse. Leaves mostly basal. Leaf-sheaths longer than adjacent culm internode; striately veined; smooth; glabrous on surface. Ligule a fringe of hairs. Collar glabrous. Leaf-blades involute; 10–25 cm long; 0.5–0.75 mm wide; stiff; glaucous. Leaf-blade surface scaberulous; glabrous.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; linear; 6–10 cm long; 0.3 cm wide. Primary panicle branches appressed; 1–2 cm long; bearing spikelets almost to the base. Panicle branches scaberulous; with insignificant pulvini.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; subterete; 6–7 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus evident; 0.5 mm long; pubescent; obtuse. Floret callus hairs 0.7 mm long.

GLUMES Glumes lower deciduous, upper persistent; similar; reaching apex of florets; thinner than fertile lemma. Lower glume lanceolate; 5.5–6 mm long; 0.9 length of upper glume; membranous; 1 -veined. Lower glume lateral veins absent. Lower glume surface asperulous. Lower glume apex acute. Upper glume lanceolate; 6–7 mm long; membranous; 1 -veined. Upper glume lateral veins absent. Upper glume surface asperulous. Upper glume apex acute.

FLORETS Fertile lemma linear; subterete; 5.5–6 mm long; coriaceous; without keel; 5 -veined. Lemma margins convolute; covering most of palea. Lemma apex awned; 3 -awned. Principal lemma awn with 3.5–4 mm long limb. Lateral lemma awns 0.5–1 mm long; shorter than principal.

FLOWER Anthers 3.

FRUIT Caryopsis with adherent pericarp; linear; 4.5 mm long. Embryo 0.25 length of caryopsis.

DISTRIBUTION Australasia: Australia.

NOTES Aristideae. Simon 1995.

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