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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.
Arrhenatherum
HABIT Perennial. Rhizomes absent (6), or elongated (1). Stolons absent (6), or present (1). Culms erect (4/4), or geniculately ascending (1/4); 17–75.64–180 cm long. Ligule an eciliate membrane. Leaf-blades filiform (1), or linear (6).
INFLORESCENCE Inflorescence a panicle.
Panicle open.
Spikelets solitary. Fertile spikelets pedicelled. Pedicels filiform (1/1), or linear (1/1); tip widened (1/1).
FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; with a barren rhachilla extension. Spikelets lanceolate (1), or oblong (6); laterally compressed; 6–10.14–16 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes elongated between glumes (1), or elongated below proximal fertile floret. Floret callus pilose (6/6).
GLUMES Glumes persistent; reaching apex of florets; thinner than fertile lemma; gaping. Lower glume lanceolate; 0.5–0.6914–0.75 length of upper glume; membranous; 1-keeled; 1 -veined (5), or 3 -veined (2). Lower glume lateral veins absent (5), or obscure (2). Lower glume surface without pits. Lower glume apex acute (4), or acuminate (3). Upper glume lanceolate (6), or ovate (1); 0.9–1.107–1.2 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined (1), or 3 -veined (6). Upper glume apex acute (4), or acuminate (3).
FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret elliptic (5), or ovate (2); 0.9–0.95–1 length of fertile lemma; chartaceous; 7 -veined (3/3); acute (4/5), or acuminate (4/5), or setaceously attenuate (1/5); awned. Fertile lemma lanceolate (1), or elliptic (5), or obovate (1); chartaceous; much thinner above; without keel; wingless; 5–6 -veined (1), or 7 -veined. Lemma surface unwrinkled; without grooves; glabrous (2), or pubescent (3), or pilose (2), or villous (1). Lemma apex entire (4), or dentate (3); 2 -fid (3/3); acuminate (4/4); muticous (4), or mucronate (2), or awned; 1 -awned. Principal lemma awn subapical; straight, or geniculate (1). Palea keels ciliolate.
FLOWER Anthers 3. Ovary pubescent all over.
FRUIT Caryopsis with adherent pericarp (6/6); lanceolate (1/3), or oblong (2/3); dorsally compressed (1/1). Embryo 0.1 length of caryopsis. Hilum linear (1/1); 0.33 length of caryopsis.
DISTRIBUTION Europe (5), or Africa (4), or Temperate Asia (4), or Australasia (1), or Pacific (1), or North America (1), or South America (1).
Please cite this publication as detailed in How to Cite Version: 3rd February 2016.
