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.

Triodia triaristata

HABIT Perennial; caespitose; clumped loosely. Butt sheaths distinctly ribbed. Culms 100 cm long. Culm-internodes scaberulous. Leaf-sheaths pubescent; outer margin hairy. Leaf-sheath oral hairs lacking to bearded. Ligule a fringe of hairs; 0.8 mm long. Collar glabrous, or pubescent. Leaf-blades straight, or curved, or flexuous; filiform; conduplicate; 20–45 cm long; 0.8–1.2 mm wide; coriaceous; stiff; resinous. Leaf-blade surface grooved on either side of midline; grooved abaxially.

INFLORESCENCE Inflorescence a panicle.

Panicle open; oblong; 16–30 cm long; 2.5–5 cm wide. Primary panicle branches simple, or sparsely divided; 6–12 cm long. Panicle axis angular. Panicle branches capillary; without exudate, or resinous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels filiform; 3–30 mm long.

FERTILE SPIKELETS Spikelets comprising 7–17 fertile florets; with diminished florets at the apex. Spikelets linear, or lanceolate; laterally compressed, or subterete; 14–27 mm long; 2–4 mm wide; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes elongated between glumes. Rhachilla elongation 0.5–0.8 mm long. Rhachilla internodes 1–1.5 mm long. Floret callus 0.2 mm long; glabrous; truncate.

GLUMES Glumes persistent; similar; shorter than spikelet; thinner than fertile lemma. Lower glume oblong; 5–13 mm long; 1 length of upper glume; scarious, or cartilaginous; without exudate, or resinous; 1-keeled; keeled above; 3 -veined. Lower glume surface smooth, or asperulous. Lower glume apex acuminate; awned; 1 -awned. Lower glume awn 1–2 mm long. Upper glume oblong; 5–13 mm long; scarious, or cartilaginous; without exudate, or resinous; 1-keeled; keeled above; 3 -veined. Upper glume surface smooth, or asperulous. Upper glume apex acuminate; awned; 1 -awned. Upper glume awn 1–2 mm long.

FLORETS Fertile lemma ovate; 4.5–5 mm long; indurate; much thinner on margins; yellow; without keel; 9 -veined. Lemma lateral veins in close groups. Lemma surface smooth; hirsute; hairy below. Lemma hairs white. Lemma apex lobed; 3 -fid; awned; 3 -awned. Principal lemma awn 3.5–5 mm long overall; limb ciliate; glabrescent towards tip. Lateral lemma awns arising on apex of lobes; 1–3 mm long; shorter than principal; ciliate. Palea oblong, or oblanceolate; 5 mm long; cartilaginous, or indurate; thinner above. Palea keels thickened (at base); winged; narrowly winged; scaberulous. Palea surface scaberulous; pubescent; hairy below. Palea apex dentate; 2 -fid; ciliate. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; cuneate; 0.8 mm long; fleshy. Anthers 3; 2.5–3 mm long.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION Australasia: Australia.

NOTES Eragrostideae. Lazarides 1996.

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