GrassBase - The Online World Grass Flora

Descriptions

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

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

Bromus

HABIT Annual (47), or perennial (105). Rhizomes absent (135), or short (9), or elongated (11). Culms erect (91/102), or geniculately ascending (58/102), or decumbent (5/102); robust (3/7), or slender (4/7); 4–64.66–200 cm long; without nodal roots (2/3), or rooting from lower nodes (3/3). Lateral branches lacking (17/18), or ample (1/18). Leaf-sheaths tubular for much of their length (10/10). Leaf-sheath auricles absent (143), or erect (1), or falcate (12). Ligule an eciliate membrane. Leaf-blades filiform (1), or linear; stiff (3), or firm (142), or flaccid (6). Leaf-blade midrib widened (1/1).

INFLORESCENCE Inflorescence a panicle, or composed of racemes (1); exserted (150), or embraced at base by subtending leaf (1). Peduncle cylindrical at apex (1/3), or tipped by a glumaceous appendage (3/3).

Panicle open (133), or contracted (28). Primary panicle branches not whorled (148), or whorled at lower nodes (1), or whorled at most nodes (2).

Racemes single (1/1); paucilateral (1/1).

Spikelets appressed (1/3), or pendulous (2/3); solitary (148/149), or in pairs (1/149), or in threes (1/149). Fertile spikelets sessile (5/149), or pedicelled (145/149); 2–3 in the cluster (1/1). Pedicels filiform (5/6), or clavate (1/6).

FERTILE SPIKELETS Spikelets comprising 1–7–30 fertile florets; with diminished florets at the apex. Spikelets linear (6/140), or lanceolate (39/140), or elliptic (14/140), or oblong (79/140), or ovate (19/140), or cuneate (16/140); laterally compressed (149), or subterete (2); 4–23.01–60 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes definite; glabrous (129), or pubescent (18), or pilose (4). Floret callus brief (147), or evident (4); glabrous (3/9), or pubescent (2/9), or pilose (4/9); obtuse (150), or pungent (1).

GLUMES Glumes persistent (149/149); shorter than spikelet (149/149); thinner than fertile lemma (11), or similar to fertile lemma in texture (140); parallel to lemmas (146), or gaping (5). Lower glume linear (23), or lanceolate (117), or elliptic (3), or oblong (8), or ovate (6); 0.3–0.7744–1 length of upper glume; membranous (110), or chartaceous (35), or herbaceous (1), or scarious (1), or coriaceous (4); without keels (106/150), or 1-keeled (44/150); 1 -veined (87), or 2 -veined (14), or 3 -veined (69), or 4 -veined (25), or 5 -veined (32), or 6–7 -veined (10), or 8–9 -veined (2). Lower glume lateral veins absent (83), or obscure (8), or distinct (66), or prominent (3). Lower glume surface smooth (146), or asperulous (3), or scabrous (6); without pits; glabrous (125), or puberulous (4), or pubescent (28), or pilose (5), or hirsute (6), or hispidulous (1). Lower glume apex obtuse (4/145), or acute (78/145), or acuminate (66/145), or attenuate (1/145), or setaceously attenuate (3/145); muticous (146), or mucronate (6), or awned (3). Upper glume linear (2), or lanceolate (129), or elliptic (14), or oblong (2), or ovate (7); 0.5–0.8132–1.4 length of adjacent fertile lemma; membranous (110), or chartaceous (35), or herbaceous (1), or scarious (1), or coriaceous (4); with undifferentiated margins (139), or hyaline margins (8), or membranous margins (2), or scarious margins (2); without keels (105/150), or 1-keeled (45/150); 3–5–13 -veined. Upper glume surface smooth (145), or asperulous (3), or scabrous (7); glabrous (126), or puberulous (5), or pubescent (29), or pilose (5), or hirsute (3), or hispidulous (1), or hispid (2). Upper glume apex obtuse (10/145), or acute (85/145), or acuminate (54/145), or attenuate (1/145), or setaceously attenuate (3/145); muticous (137), or mucronate (15), or awned (7); 1 -awned (5/5). Upper glume awn terminal (20/22), or subapical (2/22).

FLORETS Fertile lemma linear (1/149), or lanceolate (55/149), or elliptic (27/149), or oblong (66/149), or ovate (7/149), or trullate (7/149), or obovate (5/149), or oblanceolate (1/149); laterally compressed (5/5); chartaceous (129/149), or herbaceous (15/149), or coriaceous (5/149); of similar consistency above (142), or much thinner above (9); of similar consistency on margins (110), or much thinner on margins (41); without keel (124/149), or keeled (32/149); wingless; 3–7–13 -veined. Lemma midvein without distinctive roughness (146), or scaberulous (3), or scabrous (2); eciliate (149), or pubescent (2). Lemma lateral veins obscure (6/22), or with distinct primaries but obscure intermediates (4/22), or distinct (7/22), or prominent (5/22). Lemma surface smooth (126), or asperulous (3), or scaberulous (24), or scabrous (7); unwrinkled; without grooves; glabrous (95), or puberulous (18), or pubescent (61), or pilose (16), or hirsute (8), or villous (2), or hispidulous (1), or woolly (1); hairy on back (90/94), or on veins (3/94), or between veins (1/94). Lemma margins flat (145), or involute (6); eciliate (129), or ciliate (12), or pubescent (12), or pilose (1). Lemma apex entire (78), or erose (1), or dentate (75), or lobed (2); 2 -fid (76/77), or 3 -fid (1/77); incised 0.1–0.1583–0.25 of lemma length; emarginate (2/29), or truncate (1/29), or obtuse (7/29), or acute (17/29), or acuminate (5/29); muticous (6), or mucronate (2), or awned (149); 1 -awned (145/149), or 3 -awned (4/149). Principal lemma awn apical (5/149), or subapical (135/149), or from a sinus (5/149), or dorsal (5/149); straight (139/149), or curved (18/149), or geniculate (2/149); 0.2–0.7833–1.2 length of lemma. Lateral lemma awns shorter than principal (2/2). Palea embraced by lemma (149), or gaping (1), or readily splitting down midline (1); 0.6–0.8776–1 length of lemma; 2 -veined (2/2). Palea keels separated (150), or contiguous above a sulcus (1); smooth (141), or scaberulous (2), or scabrous (8); eciliate (90), or ciliolate (43), or ciliate (19). Palea surface glabrous (144), or puberulous (8), or pubescent (4). Palea apex erose (2/3), or dentate (1/3); muticous (148), or with excurrent keel veins (3). Apical sterile florets resembling fertile though underdeveloped; 3–4 in number (1/1).

FLOWER Lodicules 2 (140/140); membranous (139/139). Anthers 2 (1/150), or 3 (150/150). Stigmas 2 (2/2). Ovary with a fleshy appendage above style insertion; pubescent on apex (147/147).

FRUIT Caryopsis with adherent pericarp (144/144); linear (14/31), or lanceolate (1/31), or fusiform (4/31), or ellipsoid (9/31), or oblong (3/31), or oblanceolate (1/31); flattened (2/2); concavo-convex (3/3); apex fleshy (137/137). Hilum linear (132/132); 1 length of caryopsis.

DISTRIBUTION Europe (40), or Africa (29), or Temperate Asia (80), or Tropical Asia (28), or Australasia (22), or Pacific (10), or North America (58), or South America (43), or Antarctica (3).

Please cite this publication as detailed in How to Cite Version: 27th January 2014.