GrassBase - The Online World Grass Flora


W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Pleuropogon oregonus

HABIT Perennial. Rhizomes elongated. Culms erect; 40–90 cm long; 3–4 mm diam. Leaf-sheaths 8–20 cm long. Ligule an eciliate membrane; 2–5 mm long; lacerate. Leaf-blades 8–18 cm long; 4–7 mm wide. Leaf-blade surface scaberulous. Leaf-blade apex abruptly acute.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 1; single; bilateral; 10–15 cm long; bearing few fertile spikelets. Spikelet packing broadside to rhachis; distant.

Spikelets appressed, or ascending; solitary. Fertile spikelets pedicelled. Pedicels linear; 1–2 mm long.

FERTILE SPIKELETS Spikelets comprising 7–13 fertile florets; with diminished florets at the apex. Spikelets linear, or oblong; laterally compressed; 20–40 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 2 mm long.

GLUMES Glumes persistent; similar; shorter than spikelet; thinner than fertile lemma. Lower glume oblong; 2 mm long; 0.5–1 length of upper glume; hyaline; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume apex erose; acute. Upper glume oblong; 2–4 mm long; 0.4–0.6 length of adjacent fertile lemma; hyaline; without keels; 1 -veined. Upper glume lateral veins absent. Upper glume apex erose; acute.

FLORETS Fertile lemma ovate; 5.5–7 mm long; chartaceous; without keel; 7 -veined. Lemma apex erose; obtuse; awned; 1 -awned. Principal lemma awn 5–10 mm long overall. Palea 1 length of lemma; 2 -veined. Palea keels winged; narrowly winged (below); with each wing 1-awned (2–7mm). Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; united; oblong; fleshy; truncate. Anthers 3.

FRUIT Caryopsis with adherent pericarp. Hilum linear.

DISTRIBUTION North America: northwest USA.

NOTES Meliceae. Benson.

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