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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 album
HABIT Perennial; caespitose. Stolons present. Culms 50–125 cm long; swollen at the base; forming an ovoid corm, or moniliform corms. Culm-nodes glabrous, or bearded. Leaf-sheaths glabrous on surface, or hirsute. Ligule an eciliate membrane; 1–5 mm long; lacerate. Leaf-blades 20–40 cm long; 4–8 mm wide. Leaf-blade surface scabrous; glabrous, or hirsute.
INFLORESCENCE Inflorescence a panicle.
Panicle open; linear; dense; 10–35 cm long.
Spikelets solitary. Fertile spikelets pedicelled.
FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; with a barren rhachilla extension. Spikelets oblong; laterally compressed; 9–12 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes elongated between glumes and elongated below proximal fertile floret. Rhachilla elongation 1.5–1.8 mm long (below floret). Floret callus pilose.
GLUMES Glumes persistent; dissimilar; reaching apex of florets; thinner than fertile lemma; shiny; gaping. Lower glume lanceolate; 6–8.3 mm long; 0.66 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume primary vein scaberulous. Lower glume lateral veins absent. Lower glume apex acute. Upper glume lanceolate; 9–11 mm long; 1–1.2 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume primary vein scaberulous. Upper glume apex acute.
FLORETS Basal sterile florets male; with palea; attached to and deciduous with the fertile. Lemma of lower sterile floret elliptic; 7–10.5 mm long; chartaceous; much thinner above; pilose; hairy below; dentate; 2 -fid; acute, or acuminate; awned. Awn of lower sterile floret dorsal; arising 0.1 way up back of lemma; geniculate; 15–25 mm long. Fertile lemma elliptic; 7–10.5 mm long; chartaceous; much thinner above; without keel; 7 -veined. Lemma surface pilose; hairy below. Lemma hairs 2–3 mm long. Lemma apex acuminate; muticous, or mucronate, or awned; 1 -awned. Principal lemma awn subapical; 0–5 mm long overall. Palea keels ciliolate.
FLOWER Anthers 3; 3.3–4.7 mm long. Ovary pubescent all over.
FRUIT Caryopsis with adherent pericarp; 3.5–4 mm long.
DISTRIBUTION Europe: southwestern. Africa: north. Asia-temperate: western Asia.
NOTES Aveneae. Gr Extremad 1993.
Please cite this publication as detailed in How to Cite Version: 3rd February 2016.
