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.

Helictotrichon fluitans

HABIT Perennial. Stolons present. Culms decumbent; 40–75 cm long; 0.5–1.5 mm diam.; 3–5 -noded. Culm-internodes terete; ridged; smooth, or scaberulous. Culm-nodes glabrous. Leaf-sheaths ribbed; antrorsely scabrous. Ligule an eciliate membrane; 6.5–12 mm long; acute. Leaf-blades flat, or involute; 10–25 cm long; 2–4.5 mm wide. Leaf-blade surface ribbed; grooved adaxially and abaxially; scabrous.

INFLORESCENCE Inflorescence a panicle; embraced at base by subtending leaf.

Panicle contracted; 15–35 cm long. Primary panicle branches 2–3 -nate; 4–8.5 cm long.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels 10–20 mm long; scabrous.

FERTILE SPIKELETS Spikelets comprising 6–10 fertile florets; with a barren rhachilla extension, or with diminished florets at the apex. Spikelets oblong; laterally compressed; 9–15 mm long; breaking up at maturity; disarticulating below each fertile floret.

GLUMES Glumes persistent; similar; shorter than spikelet; thinner than fertile lemma. Lower glume lanceolate; 2.7–3.7 mm long; 0.8 length of upper glume; chartaceous; much thinner on margins; 1-keeled; 1–3 -veined. Lower glume lateral veins absent, or distinct. Lower glume apex acute. Upper glume lanceolate; 3.5–4.5 mm long; 0.9 length of adjacent fertile lemma; chartaceous; with membranous margins; 1-keeled; 3–5 -veined. Upper glume apex acute.

FLORETS Fertile lemma elliptic; 3.7–5 mm long; cartilaginous; without keel; 7 -veined. Lemma surface scabrous; glabrous, or hispidulous. Lemma apex dentate; 2 -fid; with lobes 0.3–0.6 mm long; awned; 1 -awned. Principal lemma awn dorsal; arising 0.45–0.6 way up back of lemma; straight; flat below; 11–17 mm long overall; without a column. Palea 0.3–0.75 length of lemma. Palea keels ciliate. Palea surface smooth. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; 0.9–1.23 mm long; membranous; glabrous; acute. Anthers 3; 1.5–1.7 mm long; eventually exserted, or retained within floret. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp; 1.3–1.7 mm long; light brown; glabrous. Embryo 0.1–0.2 length of caryopsis. Hilum linear; 0.25–0.3 length of caryopsis.

DISTRIBUTION Australasia: Australia and New Zealand.

NOTES Aveneae. Jacobs & Lap 1994.

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