Helictotrichon nervosum

HABIT Perennial; caespitose. Butt sheaths distinctly ribbed; glabrous. Culms erect; 60–125 cm long; 1–3 mm diam.; 2–5 -noded; without nodal roots, or rooting from lower nodes. Culm-internodes terete, or elliptical in section; ridged; smooth, or scaberulous. Culm-nodes glabrous. Leaf-sheaths ribbed; smooth, or scaberulous. Ligule an eciliate membrane; 10–20 mm long; acute. Leaf-blades flat, or involute; 15–30 cm long; 1.5–3.5 mm wide. Leaf-blade surface ribbed; grooved adaxially and abaxially; scabrous; rough adaxially, or on both sides.

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

Panicle contracted; 20–40 cm long. Primary panicle branches 2–4 -nate; 7–14 cm long.

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

FERTILE SPIKELETS Spikelets comprising 4–6 fertile florets; with a barren rhachilla extension, or with diminished florets at the apex. Spikelets oblong; laterally compressed; 10–16 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; 3.4–5 mm long; 0.8–1 length of upper glume; membranous; 1-keeled; 1–3(–5) -veined. Lower glume lateral veins absent, or distinct. Lower glume apex acute. Upper glume lanceolate; 4.5–6.2 mm long; 0.8–0.9 length of adjacent fertile lemma; membranous; 1-keeled; 3–5 -veined. Upper glume apex acute.

FLORETS Fertile lemma elliptic; 5–7.2 mm long; cartilaginous; without keel; 5–7 -veined. Lemma surface scabrous. Lemma apex dentate; 2–4 -fid; with outer lobes shorter; with lobes 0.3–0.65 mm long; awned; 1 -awned. Principal lemma awn dorsal; arising 0.45–0.6 way up back of lemma; geniculate; 12–22 mm long overall; with 7–15 mm long limb; with twisted column. Column of lemma awn 4–8.5 mm long; scabrous. Palea 0.75–0.95 length of lemma. Palea keels ciliate. Palea surface smooth, or papillose. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; 0.95–1.3 mm long; membranous; glabrous; obtuse, or acute. Anthers 3; 2.2–3 mm long; eventually exserted, or retained within floret. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp; 1.36–2.15 mm long; light brown; glabrous. Embryo 0.16–0.3 length of caryopsis. Hilum linear; 0.25–0.5 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.