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 thysanoglottis

HABIT Perennial; caespitose. Culms geniculately ascending; 75–130 cm long; 4–6 -noded. Culm-internodes ridged; distally glabrous. Leaf-sheaths mostly shorter than adjacent culm internode; pilose; with reflexed hairs; outer margin hairy. Ligule an eciliate membrane; 1.8 mm long; brown; ciliate from base of abaxial surface; erose. Leaf-blades 40–45 cm long; 7–8 mm wide. Leaf-blade surface scabrous; rough on both sides. Leaf-blade margins ciliate; hairy at base.

INFLORESCENCE Inflorescence a panicle.

Panicle open; elliptic; nodding; 24–30 cm long. Primary panicle branches drooping; 8–16 cm long; bearing 2–5 fertile spikelets on each lower branch. Panicle axis scabrous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels 20–30 mm long; scabrous.

FERTILE SPIKELETS Spikelets comprising 10–12 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 25–30 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes pubescent.

GLUMES Glumes persistent; shorter than spikelet. Lower glume lanceolate; 8.8–9.3 mm long; 0.75 length of upper glume; membranous; much thinner on margins; without keels; 1 -veined. Lower glume primary vein scabrous; eciliate, or ciliolate. Lower glume lateral veins absent. Lower glume apex setaceously attenuate. Upper glume lanceolate; 10.2–12.8 mm long; 0.9 length of adjacent fertile lemma; membranous; with hyaline margins; without keels; 3 -veined. Upper glume primary vein scabrous. Upper glume surface glabrous, or pubescent. Upper glume apex setaceously attenuate.

FLORETS Fertile lemma elliptic; 11.6–12.8 mm long; chartaceous; much thinner on margins; without keel; 7 -veined. Lemma surface pubescent. Lemma margins ciliate. Lemma apex acute; awned; 1 -awned. Principal lemma awn subapical; 3.5–4.5 mm long overall. Palea elliptic; 10.9–11 mm long. Palea surface glabrous, or puberulous; hairy on back. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; membranous. Anthers 3; 2.3–2.4 mm long; orange. Ovary with a fleshy appendage above style insertion; pubescent on apex.

FRUIT Caryopsis with adherent pericarp; hairy at apex; apex fleshy. Hilum linear.

DISTRIBUTION North America: Mexico.

NOTES Bromeae. Sod, & Beaman 2001.

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