Helictotrichon umbrosum

HABIT Perennial. Rhizomes elongated. Butt sheaths dark brown. Culms erect, or geniculately ascending; 60–90 cm long. Ligule an eciliate membrane; 2 mm long. Leaf-blades flat, or involute; 10–20 cm long; 1–5 mm wide. Leaf-blade surface pubescent; sparsely hairy; hairy adaxially.

INFLORESCENCE Inflorescence a panicle.

Panicle open; linear; dense, or loose; 7–20 cm long. Primary panicle branches appressed. Panicle branches straight, or flexuous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 2–4 fertile florets; with a barren rhachilla extension. Spikelets oblong; laterally compressed; 9–16 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 2–2.5 mm long; pilose; hairy above. Floret callus pilose.

GLUMES Glumes persistent; similar; shorter than spikelet; thinner than fertile lemma. Lower glume elliptic; 3–7 mm long; 0.6–0.8 length of upper glume; hyaline; 1-keeled; 1(–3) -veined. Lower glume lateral veins absent, or obscure. Lower glume apex acute. Upper glume oblong; 5–9 mm long; 0.7–0.9 length of adjacent fertile lemma; hyaline; 1-keeled; 3 -veined. Upper glume apex acute.

FLORETS Fertile lemma elliptic; 7–10 mm long; membranous; without keel; 5–7 -veined. Lemma apex dentate; 2 -fid; acute, or setaceously attenuate; awned; 1 -awned. Principal lemma awn dorsal; arising 0.5–0.6 way up back of lemma; geniculate; 13–20 mm long overall; with twisted column. Palea keels ciliolate. Rhachilla extension 0.75 length of fertile floret; pilose.

FLOWER Anthers 3; 2 mm long. Ovary pubescent on apex.

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

DISTRIBUTION Africa: northeast tropical and east tropical.

NOTES Aveneae. FTEA.

ADDITIONAL CHARACTERS Rhachilla hairs shorter than itself.

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