Bromus tectorum

HABIT Annual; culms solitary, or caespitose. Culms erect, or geniculately ascending; 5–60 cm long; 2–5 -noded. Leaf-sheaths hispid. Ligule an eciliate membrane; 2–5 mm long; lacerate. Leaf-blades 2–16 cm long; 1.5–4 mm wide. Leaf-blade surface pubescent.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; oblong; interrupted (branches clustered); nodding; 4–18 cm long. Primary panicle branches drooping; bearing 5–8 fertile spikelets on each lower branch. Panicle branches flexuous; scaberulous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1–8 fertile florets; with diminished florets at the apex. Spikelets cuneate; laterally compressed; 10–25 mm long; breaking up at maturity; disarticulating below each fertile floret.

GLUMES Glumes persistent; dissimilar; shorter than spikelet; gaping. Lower glume linear; 6–11 mm long; 0.7–0.8 length of upper glume; chartaceous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume apex acuminate. Upper glume lanceolate; 6–13 mm long; 0.7–0.8 length of adjacent fertile lemma; chartaceous; 1-keeled; 3 -veined. Upper glume apex acute.

FLORETS Fertile lemma lanceolate; 9–16 mm long; chartaceous; much thinner on margins; without keel; 5–7 -veined. Lemma surface scaberulous; glabrous, or hirsute. Lemma apex dentate; 2 -fid; incised 0.2 of lemma length; awned; 1 -awned. Principal lemma awn subapical; 10–25 mm long overall; limb scabrous. Palea 0.8 length of lemma. Palea keels ciliolate. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; membranous. Anthers 3; 0.5–1 mm long. Ovary with a fleshy appendage above style insertion; pubescent on apex.

FRUIT Caryopsis with adherent pericarp; linear; hairy at apex; apex fleshy. Hilum linear; 1 length of caryopsis.

DISTRIBUTION Europe: northern, central, southwestern, southeastern, and eastern. Africa: north, Macaronesia, and south. Asia-temperate: Siberia, Soviet far east, Soviet Middle Asia, Caucasus, western Asia, Arabia, China, and eastern Asia. Asia-tropical: India. Australasia: Australia and New Zealand. Pacific: north-central. North America: Subarctic, western Canada, eastern Canada, northwest USA, north-central USA, northeast USA, southwest USA, south-central USA, southeast USA, and Mexico. South America: southern South America.

NOTES Bromeae. Acedo 1996.

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