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.

Rytidosperma racemosum

HABIT Perennial; caespitose. Culms erect; 20–60 cm long; 3–4 -noded. Culm-nodes glabrous. Leaf-sheaths glabrous on surface, or hirsute; with tubercle-based hairs. Ligule a fringe of hairs; 0.25 mm long. Leaf-blades involute; 5–15 cm long; 1–2 mm wide. Leaf-blade surface scabrous; rough adaxially; glabrous, or pilose; hairy abaxially; with tubercle-based hairs.

INFLORESCENCE Inflorescence a panicle.

Panicle open; linear; equilateral; 5–15 cm long. Primary panicle branches indistinct the panicle almost racemose. Panicle axis scabrous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels scabrous.

FERTILE SPIKELETS Spikelets comprising 6–10 fertile florets; with diminished florets at the apex. Spikelets cuneate; laterally compressed; 9–18 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus elongated; 1.5–2 mm long; pubescent.

GLUMES Glumes persistent; similar; shorter than spikelet; thinner than fertile lemma. Lower glume lanceolate; 7–16 mm long; 1 length of upper glume; membranous; much thinner on margins; without keels; 5–7 -veined. Lower glume surface asperulous; rough on veins. Lower glume apex truncate, or acute. Upper glume lanceolate; 7–16 mm long; 0.9–1.3 length of adjacent fertile lemma; membranous; with hyaline margins; without keels; 5–7 -veined. Upper glume surface asperulous; rough on veins. Upper glume apex truncate, or acute.

FLORETS Fertile lemma oblong; 8–12 mm long; chartaceous; pallid; shiny; without keel; 9 -veined. Lemma surface with a transverse fringe of hair and with marginal hair tufts (above, with or without dorsal tufts). Lemma apex lobed; 2 -fid; with oblong lobes; with lobes 5–6 mm long; incised 0.6 of lemma length; acute; awned; 1 -awned, or 3 -awned. Principal lemma awn from a sinus; geniculate; 14 mm long overall; with twisted column. Column of lemma awn 4 mm long. Lateral lemma awns arising on apex of lobes; 7 mm long. Palea elliptic; 4–5 mm long. Palea keels ciliolate. Palea surface glabrous, or pilose; hairy on flanks; hairy below. Palea apex emarginate, or obtuse. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; fleshy; ciliate. Anthers 3; 1.5–2 mm long.

FRUIT Caryopsis with adherent pericarp; obovoid; 2.5 mm long.

DISTRIBUTION Australasia: Australia and New Zealand.

NOTES Arundineae. Vickery 1993.

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