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.

Bromus racemosus

HABIT Annual; culms solitary, or caespitose. Culms erect, or geniculately ascending; 10–140 cm long; 2–7(–9) -noded. Leaf-sheaths pubescent, or pilose. Ligule an eciliate membrane; 0.6–2.1 mm long; erose; truncate, or obtuse. Leaf-blades 5–20 cm long; 2–5(–9) mm wide. Leaf-blade surface hirsute.

INFLORESCENCE Inflorescence a panicle.

Panicle open; lanceolate, or ovate; equilateral, or nodding; (4–)6–19(–22) cm long. Primary panicle branches ascending, or drooping; (1–)2–9(–13) cm long; bearing 1–4 fertile spikelets on each lower branch.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels 5–25 mm long.

FERTILE SPIKELETS Spikelets comprising (5–)6–10(–13) fertile florets; with diminished florets at the apex. Spikelets lanceolate, or oblong; laterally compressed; compressed slightly; (11–)15–25(–31) mm long; 3.5–5 mm wide; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 0.7–1.7 mm long.

GLUMES Glumes persistent; similar; shorter than spikelet; thinner than fertile lemma; parallel to lemmas. Lower glume lanceolate, or oblong; (4–)5–8(–9) mm long; 0.9 length of upper glume; chartaceous; without keels; 3–5 -veined. Lower glume apex acute. Upper glume elliptic, or ovate; (4.8–)6–9(–10) mm long; 0.8–0.9 length of adjacent fertile lemma; chartaceous; without keels; 5–9 -veined. Upper glume apex acute; muticous, or mucronate.

FLORETS Fertile lemma elliptic, or obovate; (6–)7.5–11(–12) mm long; cartilaginous; much thinner on margins; without keel; 7–11 -veined. Lemma lateral veins prominent. Lemma surface scaberulous. Lemma margins flat. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn subapical; straight, or flexuous; (4–)6.5–10(–11.5) mm long overall. Palea 0.8–0.9 length of lemma. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; 1–2 mm long; membranous. Anthers 3; (0.5–)1–2.5(–3.2) mm long. Ovary with a fleshy appendage above style insertion; pubescent on apex.

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

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

NOTES Bromeae. Gr. Brit. Isles 2014.

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