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 helmsii

HABIT Perennial; caespitose. Culms erect; 80 cm long; 2 -noded. Lateral branches lacking. Leaf-sheath oral hairs ciliate; 2 mm long. Ligule a fringe of hairs. Leaf-blades aciculate; conduplicate; 7–14 cm long; 2 mm wide; coriaceous; stiff. Leaf-blade surface pubescent; hairy adaxially. Leaf-blade margins unthickened. Leaf-blade apex pungent.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; oblong; 10–14 cm long; 1.5–2 cm wide. Primary panicle branches 1 -nate. Panicle axis scaberulous. Panicle branches scaberulous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels 1–2 mm long; scaberulous.

FERTILE SPIKELETS Spikelets comprising 3–4 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 12–15 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 2–3 mm long; pubescent. Floret callus 1 mm long; pubescent; acute.

GLUMES Glumes persistent; similar; reaching apex of florets. Lower glume lanceolate; 12–15 mm long; 1 length of upper glume; chartaceous; much thinner on margins; without keels; 5–7 -veined. Lower glume surface asperulous. Lower glume apex acuminate. Upper glume lanceolate; 12–15 mm long; 3 length of adjacent fertile lemma; chartaceous; with membranous margins; without keels; 5 -veined. Upper glume surface asperulous. Upper glume apex acuminate.

FLORETS Fertile lemma oblong; 4.5–5 mm long; coriaceous; without keel; 3 -veined. Lemma surface pubescent. Lemma apex lobed; 3 -fid; awned; 3 -awned. Principal lemma awn curved; pseudo-articulate across body of lemma; 8–12 mm long overall. Lateral lemma awns arising on apex of lobes; 6–8 mm long; shorter than principal. Palea oblong; 5–5.5 mm long; 2 -veined. Palea keels winged; narrowly winged; ciliolate. Palea surface glabrous. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; fleshy. Anthers 3; 2–2.3 mm long.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION Australasia: Australia.

NOTES Eragrostideae. CEH 1994.

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