Bromus arvensis

HABIT Annual; culms solitary, or caespitose. Culms erect, or geniculately ascending; 25–90 cm long; 2–8 -noded. Leaf-sheaths pubescent. Ligule an eciliate membrane; 1–4 mm long; erose. Leaf-blades 5–20 cm long; 2–6(–10) mm wide. Leaf-blade surface scaberulous; pilose.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; elliptic, or ovate; equilateral, or nodding; 8–25 cm long; 6–20 cm wide. Primary panicle branches spreading; bearing 1–8 fertile spikelets on each lower branch. Panicle branches flexuous; scaberulous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels 10–30 mm long.

FERTILE SPIKELETS Spikelets comprising 4–10 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 20–24 mm long; 3–6 mm wide; breaking up at maturity; disarticulating below each fertile floret.

GLUMES Glumes persistent; dissimilar; shorter than spikelet; parallel to lemmas. Lower glume lanceolate; 4–6 mm long; 0.6–0.9 length of upper glume; chartaceous; much thinner above; 1-keeled; 3(–5) -veined. Lower glume apex acute. Upper glume elliptic; 6–8 mm long; 0.8–0.9 length of adjacent fertile lemma; chartaceous; with membranous margins; 1-keeled; 5–7(–9) -veined. Upper glume apex acute.

FLORETS Fertile lemma elliptic; 7–9 mm long; chartaceous; much thinner above; much thinner on margins; without keel; 7 -veined. Lemma surface scaberulous. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn subapical; 6–10 mm long overall; limb scabrous. Palea 1 length of lemma. Palea keels ciliolate. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; membranous. Anthers 3; 3–4.5 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. Asia-temperate: Siberia, Soviet far east, Soviet Middle Asia, Caucasus, western Asia, Arabia, and China. North America: western Canada, eastern Canada, north-central USA, northeast USA, southwest USA, and southeast USA. South America: southern South America.

NOTES Bromeae. Acedo 1996.

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