Helictotrichon quadridentulum

HABIT Perennial; caespitose. Butt sheaths thickened and forming a bulb. Culms erect; 40–135 cm long. Leaf-sheaths longer than adjacent culm internode; smooth, or scaberulous. Ligule an eciliate membrane; 4–12 mm long. Leaf-blades 8–30 cm long; 1–5 mm wide. Leaf-blade surface scabrous; rough on both sides.

INFLORESCENCE Inflorescence a panicle.

Panicle open; linear, or oblong; 10–35 cm long. Primary panicle branches ascending, or spreading; 3–7 cm long.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 2–6 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 5–10 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes glabrous.

GLUMES Glumes persistent; similar; shorter than spikelet; thinner than fertile lemma. Lower glume elliptic; 2–4 mm long; 0.66–0.75 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute. Upper glume elliptic; 3–5 mm long; 1 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume apex acute.

FLORETS Fertile lemma lanceolate; 3–5 mm long; cartilaginous; without keel; 7 -veined. Lemma surface scabrous. Lemma apex dentate; 2 -fid; with lateral lobes bidentate; awned; 1 -awned. Principal lemma awn dorsal; arising 0.75–0.85 way up back of lemma; geniculate; 2–6 mm long overall; with twisted column. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Anthers 3. Ovary pubescent on apex.

FRUIT Caryopsis with adherent pericarp; hairy at apex. Hilum linear.

DISTRIBUTION South America: Brazil and southern South America.

NOTES Aveneae. Swallen 1995.

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