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.

Rytidosperma mamberamense

HABIT Perennial; caespitose; clumped densely. Culms erect; 20–35 cm long; 3–5 -noded. Ligule a fringe of hairs. Leaf-blades filiform; involute; 22–35 cm long; 1–2 mm wide. Leaf-blade surface scabrous; rough adaxially; glabrous. Leaf-blade margins scabrous. Leaf-blade apex obtuse.

INFLORESCENCE Inflorescence a panicle. Peduncle glabrous.

Panicle open, or contracted; lanceolate, or oblong; 4–6 cm long. Primary panicle branches appressed, or ascending; 2–3 -nate; whorled at lower nodes; 0.2–0.6 cm long. Panicle branches flexuous; glabrous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 4 fertile florets; with diminished florets at the apex. Spikelets obovate; laterally compressed; 7–8 mm long; breaking up at maturity; disarticulating below each fertile floret.

GLUMES Glumes persistent; similar; exceeding apex of florets; thinner than fertile lemma; gaping. Lower glume lanceolate; 8–8.5 mm long; 1 length of upper glume; membranous; without keels; 5 -veined. Lower glume surface smooth; glabrous. Lower glume margins ciliolate (above). Lower glume apex acute. Upper glume lanceolate; 8–8.5 mm long; 1.2–1.6 length of adjacent fertile lemma; membranous; without keels; 5 -veined. Upper glume surface smooth; glabrous. Upper glume margins ciliolate (above). Upper glume apex acute.

FLORETS Fertile lemma ovate; 5–7 mm long; chartaceous; without keel; 9 -veined. Lemma surface glabrous; with a transverse fringe of hair. Lemma margins scabrous. Lemma apex lobed; 2 -fid; with lobes 2.5–3 mm long; incised 0.5 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; straight, or geniculate; simple at base; 4.5–8.5 mm long overall; without a column, or with a straight or slightly twisted column. Palea elliptic; 5–9 mm long. Palea keels ciliolate. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; cuneate; fleshy. Anthers 3; 1.8–2.5 mm long.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION Asia-tropical: Papuasia.

NOTES Arundineae. Jansen 1999.

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