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 vickeryae

HABIT Perennial; caespitose. Culms erect; 50–100 cm long; 1–3 mm diam.; 4–5 -noded. Culm-internodes terete, or elliptical in section; ridged; smooth. Culm-nodes glabrous. Leaf-sheaths ribbed; smooth, or scaberulous. Ligule an eciliate membrane; 9–12 mm long; acute. Leaf-blades 15–35 cm long; 3–4 mm wide. Leaf-blade surface ribbed; grooved adaxially and abaxially; scabrous; rough adaxially.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; 7–15 cm long. Primary panicle branches 2–3 -nate; 2–5 cm long. Panicle branches flexuous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels 5–10 mm long.

FERTILE SPIKELETS Spikelets comprising 3–4 fertile florets; with a barren rhachilla extension, or with diminished florets at the apex. Spikelets oblong; laterally compressed; 8–11 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; 3.2–3.4 mm long; 0.9 length of upper glume; membranous; 1-keeled; 3 -veined. Lower glume apex acute. Upper glume lanceolate; 3.6–4 mm long; 0.7 length of adjacent fertile lemma; membranous; 1-keeled; 5 -veined. Upper glume apex acute.

FLORETS Fertile lemma elliptic; 5–5.5 mm long; cartilaginous; without keel; 7 -veined. Lemma surface scabrous; rough on veins. Lemma apex dentate; 4 -fid; with simple equal lobes, or with outer lobes shorter; with lobes 0.5–1 mm long; awned; 5 -awned. Principal lemma awn dorsal; arising 0.5–0.55 way up back of lemma; geniculate; flat below; 10–12 mm long overall; with 6–7.5 mm long limb; with twisted column. Column of lemma awn 4–5 mm long; scabrous. Lateral lemma awns arising on apex of lobes; 0.5 mm long; shorter than principal. Palea 0.8 length of lemma. Palea keels ciliate. Palea surface papillose. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; 0.98–1.12 mm long; membranous; glabrous; acute. Anthers 3; 1.7–1.8 mm long; eventually exserted. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp; 1.9 mm long; dark brown; glabrous. Embryo 0.35 length of caryopsis. Hilum linear; 0.3–0.35 length of caryopsis.

DISTRIBUTION Australasia: Australia.

NOTES Aveneae. Jacobs & Lap 1994.

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