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 diemenicum

HABIT Perennial; caespitose. Rhizomes absent, or short. Butt sheaths pallid; glossy. Culms 15–35 cm long; 4–5 -noded. Culm-internodes smooth. Leaf-sheaths ribbed; glabrous on surface, or pilose. Leaf-sheath oral hairs ciliate. Ligule a fringe of hairs; 0.5 mm long. Leaf-blades involute; 12–25 cm long; 2–3 mm wide. Leaf-blade surface glabrous, or pilose.

INFLORESCENCE Inflorescence a panicle; comprising 10–15 fertile spikelets. Peduncle scaberulous above.

Panicle open; lanceolate, or ovate; 3–5 cm long; bearing few spikelets. Panicle axis scabrous. Panicle branches scabrous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels scabrous.

FERTILE SPIKELETS Spikelets comprising 4–6 fertile florets; with diminished florets at the apex. Spikelets cuneate; laterally compressed; (10–)12–15(–18) mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 0.5 mm long. Floret callus pilose. Floret callus hairs 1–2 mm long.

GLUMES Glumes persistent; similar; exceeding apex of florets; thinner than fertile lemma. Lower glume lanceolate; 10–18 mm long; 1 length of upper glume; membranous; purple; without keels; 3–5 -veined. Lower glume apex acute. Upper glume lanceolate; 10–18 mm long; membranous; purple; without keels; 3–5 -veined. Upper glume apex acute.

FLORETS Fertile lemma oblong; 8–10.5 mm long; chartaceous; shiny; without keel; 9 -veined. Lemma surface with 2 transverse rows of hair tufts. Lemma hairs 2–4 mm long. Lemma apex lobed; 2 -fid; with lobes 3 mm long; incised 0.5 of lemma length; awned; 3 -awned. Principal lemma awn from a sinus; geniculate; 11 mm long overall; with twisted column. Column of lemma awn 3–4 mm long. Lateral lemma awns 2–2.5 mm long. Palea elliptic; 4.5–6.5 mm long; thinner above. Palea keels ciliolate. Palea surface glabrous, or pilose; hairy on margins; hairy in the middle. Palea apex emarginate, or truncate. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; fleshy. Anthers 3; 1.25 mm long; yellow.

FRUIT Caryopsis with adherent pericarp; obovoid; 1.75–2 mm long.

DISTRIBUTION Australasia: Australia.

NOTES Arundineae. Morris 1997.

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