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.

Panicum effusum

HABIT Perennial; caespitose. Rootstock evident. Butt sheaths villous. Basal innovations extravaginal. Culms erect, or geniculately ascending; 15–100 cm long; 2–3 -noded. Culm-internodes smooth, or scaberulous. Culm-nodes glabrous, or pubescent. Lateral branches lacking, or sparse. Leaves mostly basal. Leaf-sheaths pilose; with tubercle-based hairs. Ligule a ciliate membrane; 1 mm long. Leaf-blades flat, or involute; 5–25 cm long; 2–5.5 mm wide. Leaf-blade midrib prominent beneath. Leaf-blade surface ribbed; scabrous; pilose; sparsely hairy, or moderately hairy; hairy on both sides; with tubercle-based hairs. Leaf-blade apex attenuate.

INFLORESCENCE Inflorescence a panicle; deciduous as a whole; embraced at base by subtending leaf.

Panicle open; oblong; effuse; 8–50 cm long; with spikelets clustered towards branch tips. Primary panicle branches spreading; 1–4 -nate; profusely divided; branching divaricately; 10–20 cm long. Panicle branches stiff; scabrous; glabrous; glabrous in axils, or pubescent in axils.

Spikelets in pairs. Fertile spikelets pedicelled. Pedicels 2–10 mm long; tip discoid.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate, or ovate; dorsally compressed; acute, or acuminate; 2.25–2.75 mm long; falling entire; deciduous with accessory branch structures; readily shedding fertile florets.

GLUMES Glumes reaching apex of florets; thinner than fertile lemma. Lower glume ovate; 0.5(–0.66) length of spikelet; membranous; without keels; 3–5 -veined. Lower glume apex acute, or acuminate. Upper glume ovate; 1 length of spikelet; membranous; without keels; 5 -veined. Upper glume apex acute.

FLORETS Basal sterile florets barren; with palea. Lemma of lower sterile floret similar to upper glume; elliptic; 0.9 length of spikelet; membranous; 7 -veined; acuminate. Palea of lower sterile floret 0.5 length of lemma. Fertile lemma elliptic, or orbicular; dorsally compressed; 1.5–1.75 mm long; indurate; light brown; dull, or shiny; without keel. Lemma surface smooth, or papillose. Lemma margins involute. Lemma apex obtuse. Palea involute; indurate.

FLOWER Anthers 3.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION Asia-tropical: Papuasia. Australasia: Australia.

NOTES Paniceae. Fl NSW 1993.

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