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 radonensis

HABIT Perennial; caespitose. Butt sheaths indurate. Culms rambling; 150–250 cm long; 5–10 mm diam. Culm-internodes terete, or elliptical in section. Leaf-sheaths loose; longer than adjacent culm internode; resinous; smooth; glabrous on surface; outer margin glabrous, or hairy. Leaf-sheath oral hairs bearded; 3.5 mm long. Ligule a fringe of hairs; 1 mm long. Leaf-blades conduplicate, or convolute; 30–60 cm long; 2–5 mm wide; coriaceous; stiff; resinous. Leaf-blade surface grooved on either side of midline; grooved abaxially; scaberulous; rough adaxially; glabrous. Leaf-blade margins cartilaginous; spinulose. Leaf-blade apex pungent.

INFLORESCENCE Inflorescence a panicle.

Panicle open; elliptic; 14–25 cm long; 7–15 cm wide. Primary panicle branches 1–3 -nate; 3–7 cm long. Panicle axis angular; smooth, or scaberulous. Panicle branches scabrous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels filiform; 3–25 mm long; scabrous.

FERTILE SPIKELETS Spikelets comprising 5–7 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 5–8 mm long; 4–5 mm wide; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes flattened; curved; 0.5–0.8 mm long; smooth, or scaberulous. Floret callus glabrous; truncate.

GLUMES Glumes persistent; similar; shorter than spikelet; thinner than fertile lemma. Lower glume oblong; 2–2.5 mm long; 1 length of upper glume; membranous; without keels; 3 -veined. Lower glume primary vein scabrous. Lower glume surface convex, or flat. Lower glume margins ciliolate. Lower glume apex dentate; 2 -fid; obtuse. Upper glume oblong; 2–2.5 mm long; membranous; without keels; 3 -veined. Upper glume primary vein scabrous. Upper glume margins ciliolate. Upper glume apex dentate; 2 -fid; obtuse.

FLORETS Fertile florets divergent. Fertile lemma obovate; 2–3 mm long; coriaceous; much thinner on margins; shiny; without keel; 3 -veined. Lemma surface scaberulous; rough above. Lemma margins scaberulous. Lemma apex lobed; 2 -fid; mucronate. Principal lemma awn from a sinus. Palea obovate; 1 length of lemma; coriaceous; thinner above. Palea keels thickened; scaberulous. Palea apex erose; obtuse; ciliate. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; fleshy. Anthers 3; 1.3–2 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.