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.

Agropyron retrofractum

HABIT Perennial; caespitose. Culms erect; 20–35 cm long; 2–3 -noded. Culm-nodes glabrous. Leaf-sheaths glabrous on surface. Leaf-sheath auricles absent. Ligule an eciliate membrane; 0.5 mm long; truncate. Leaf-blades flat, or involute; 5–15 cm long; 1–2 mm wide; grey-green. Leaf-blade surface ribbed; scabrous; pubescent.

INFLORESCENCE Inflorescence composed of racemes. Peduncle hirsute above.

Racemes 1; single; linear, or oblong; bilateral; 1.5–6 cm long; 8–15 mm wide; bearing few fertile spikelets, or many spikelets; bearing 4–10 fertile spikelets on each. Rhachis pubescent on surface. Spikelet packing broadside to rhachis; contiguous. Rhachis internodes oblong.

Spikelets ascending; solitary. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 5–9 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 10–20 mm long; breaking up at maturity; disarticulating below each fertile floret.

GLUMES Glumes persistent; similar; shorter than spikelet; similar to fertile lemma in texture; gaping. Lower glume lanceolate; 6–7 mm long; 1 length of upper glume; coriaceous; 1-keeled; keeled all along; 5 -veined. Lower glume apex acuminate. Upper glume lanceolate; 5–7 mm long; 0.66–0.75 length of adjacent fertile lemma; coriaceous; 1-keeled; 7 -veined. Upper glume apex acuminate.

FLORETS Fertile lemma ovate; 9–10 mm long; coriaceous; keeled; keeled above; 5–7 -veined. Lemma surface asperulous; rough above. Lemma apex acuminate; mucronate, or awned; 1 -awned. Principal lemma awn 0.5–3 mm long overall. Palea 6–7 mm long. Palea keels scabrous. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Anthers 3; 2.5 mm long. Ovary with a fleshy appendage below style insertion; pubescent on apex.

FRUIT Caryopsis with adherent pericarp; linear; hairy at apex; apex fleshy. Hilum linear. Disseminule comprising a floret.

DISTRIBUTION Australasia: Australia and New Zealand.

NOTES Triticeae. Vickery 1993.

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