Trisetum palmeri

HABIT Perennial; caespitose. Culms slender; 60–100 cm long; 1–2 mm diam. Lateral branches lacking. Leaf-sheaths smooth, or scaberulous; glabrous on surface. Ligule an eciliate membrane; 3–4 mm long. Leaf-blades 10–20 cm long; 1–3 mm wide. Leaf-blade surface scabrous.

INFLORESCENCE Inflorescence a panicle.

Panicle open; lanceolate; 10–20 cm long. Primary panicle branches ascending; whorled at most nodes; 2–5 cm long. Panicle branches scabrous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 2 fertile florets; with a barren rhachilla extension. Spikelets oblong; laterally compressed; 5–6 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 1 mm long; pilose; with 1 mm long hairs. Floret callus pubescent.

GLUMES Glumes persistent; similar; shorter than spikelet; thinner than fertile lemma; shiny; gaping. Lower glume lanceolate; 4–5 mm long; 1 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume primary vein scabrous. Lower glume lateral veins absent. Lower glume apex acute. Upper glume lanceolate; 4–5 mm long; 1 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume primary vein scabrous. Upper glume apex acute.

FLORETS Fertile lemma lanceolate; (4–)5 mm long; membranous; much thinner above; keeled; 5 -veined. Lemma surface asperulous. Lemma apex dentate; 2 -fid; obtuse; awned; 1 -awned. Principal lemma awn dorsal; arising 0.5 way up back of lemma; geniculate; 5–6 mm long overall; with twisted column. Palea gaping; 1 length of lemma; hyaline. Rhachilla extension 1.5 mm long; pilose.

FLOWER Anthers 3; 2.5 mm long. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp. Hilum punctiform. Endosperm liquid.

DISTRIBUTION North America: Mexico.

NOTES Aveneae. Fl Nov Gal 1994.

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