Helictotrichon mortonianum

HABIT Perennial; caespitose; clumped densely. Culms 10–20 cm long. Ligule an eciliate membrane. Leaf-blades erect; involute; 3–8 cm long; 1 mm wide; stiff.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; linear, or oblong; 2–5 cm long; bearing few spikelets. Primary panicle branches appressed; bearing 1 fertile spikelets on each lower branch.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 2 fertile florets; with a barren rhachilla extension. Spikelets oblong, or cuneate; laterally compressed; 10–12 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes pilose. Floret callus pilose. Floret callus hairs 2 mm long.

GLUMES Glumes persistent; similar; exceeding apex of florets; thinner than fertile lemma. Lower glume lanceolate; 10–12 mm long; 1 length of upper glume; membranous; 1-keeled; 3 -veined. Lower glume apex acuminate. Upper glume lanceolate; 10–12 mm long; 1.5 length of adjacent fertile lemma; membranous; 1-keeled; 3–5 -veined. Upper glume apex acuminate.

FLORETS Fertile lemma elliptic; 6–7 mm long; cartilaginous; without keel. Lemma apex dentate; 4 -fid; awned; 1 -awned. Principal lemma awn dorsal; arising 0.5 way up back of lemma; geniculate; 10–15 mm long overall; with twisted column.

FLOWER Anthers 3. Ovary pubescent on apex.

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

DISTRIBUTION North America: northwest USA, southwest USA, and south-central USA.

NOTES Aveneae. Man US Gr 1994.

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