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.

Avena

HABIT Annual. Culms erect (18), or geniculately ascending (13), or decumbent (2), or prostrate (1); 7–71.73–180 cm long. Lateral branches lacking (13/13). Ligule an eciliate membrane.

INFLORESCENCE Inflorescence a panicle.

Panicle open (20), or contracted (1).

Spikelets pendulous (19/19); solitary. Fertile spikelets pedicelled. Pedicels filiform.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets (1), or 2 fertile florets (17), or 3 fertile florets (19), or 4 fertile florets (9), or 5 fertile florets (4), or 6 fertile florets (1); with a barren rhachilla extension. Spikelets lanceolate (13), or cuneate (8); laterally compressed; 11–24.4–50 mm long; persistent on plant (6), or breaking up at maturity (15); disarticulating below each fertile floret (7/15), or above glumes but not between florets (8/15). Rhachilla internodes definite; glabrous (17), or pilose (4). Floret callus brief (6), or evident (12), or elongated (3); glabrous (5/18), or pubescent (1/18), or bearded (12/18); obtuse (19), or acute (1), or pungent (1).

GLUMES Glumes persistent (15/15); shorter than spikelet (2), or reaching apex of florets (1), or exceeding apex of florets (18); thinner than fertile lemma (20), or similar to fertile lemma in texture (1); parallel to lemmas (2), or gaping (19). Lower glume lanceolate; 0.5–0.9517–1 length of upper glume; membranous; without keels; 3–4 -veined (2), or 5 -veined (4), or 6 -veined (2), or 7 -veined (17), or 8 -veined (13), or 9 -veined (15), or 10–11 -veined (4). Lower glume surface without pits. Lower glume apex obtuse (1), or acute (1), or acuminate (20). Upper glume lanceolate (8), or elliptic (13); 0.8–1.366–2.5 length of adjacent fertile lemma; membranous; without keels; 5–6 -veined (1), or 7 -veined (17), or 8 -veined (14), or 9 -veined (18), or 10–11 -veined (4). Upper glume apex obtuse (1), or acute (1), or acuminate (20).

FLORETS Fertile lemma lanceolate; membranous (1), or coriaceous (20); of similar consistency above (1), or much thinner above (20); without keel; wingless; 7 -veined (20), or 8 -veined (4), or 9 -veined (5). Lemma lateral veins distinct (1/1). Lemma surface smooth (13), or scaberulous (5), or scabrous (3); unwrinkled; without grooves; glabrous (13), or pilose (11), or villous (1). Lemma margins eciliate, or ciliate (1). Lemma apex dentate; 2 -fid, or 3–4 -fid (5); acuminate (1/1); muticous (3), or awned (19); 0 -awned (1/19), or 1 -awned (8/19), or 3 -awned (11/19). Principal lemma awn subapical (1/19), or dorsal (19/19); straight (1/19), or curved (2/19), or geniculate (17/19). Column of lemma awn glabrous (14/17), or hispidulous (1/17), or puberulous (2/17), or pubescent (2/17). Lateral lemma awns shorter than principal (11/11). Palea 0.5 length of lemma. Palea keels wingless (19), or winged (2); eciliate (4), or ciliolate (14), or ciliate (3). Palea surface glabrous (20), or pubescent (1).

FLOWER Anthers 3. Ovary pubescent on apex (1), or pubescent all over (20).

FRUIT Caryopsis with adherent pericarp; oblong (1/1). Hilum linear.

DISTRIBUTION Europe (17), or Africa (14), or Temperate Asia (13), or Tropical Asia (5), or Australasia (7), or Pacific (3), or North America (4), or South America (7), or Antarctica (1).

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