Panicum diffusum

HABIT Perennial; caespitose. Culms geniculately ascending, or decumbent; slender; 20–100 cm long; wiry. Culm-nodes pubescent. Lateral branches ample. Leaf-sheaths glabrous on surface, or hirsute; with tubercle-based hairs; outer margin hairy. Ligule a fringe of hairs; 1.5–3 mm long. Leaf-blades 5–20 cm long; 1–4.5 mm wide; mid-green. Leaf-blade surface glabrous, or pilose; hairy on both sides.

INFLORESCENCE Inflorescence a panicle; terminal and axillary. Axillary inflorescences compact, or enclosed.

Panicle open; pyramidal; 5–25 cm long; with spikelets clustered towards branch tips. Primary panicle branches ascending, or spreading. Panicle branches scabrous; glabrous in axils.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets ovate; dorsally compressed; acute; 2.1–2.7 mm long; 1 mm wide; falling entire.

GLUMES Glumes dissimilar; reaching apex of florets; thinner than fertile lemma. Lower glume ovate; 0.5 length of spikelet; membranous; without keels; 3 -veined. Lower glume apex acute. Upper glume ovate; 1 length of spikelet; membranous; without keels; 5 -veined. Upper glume apex acute.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret similar to upper glume; ovate; 1 length of spikelet; membranous; 5 -veined; acute. Fertile lemma elliptic; dorsally compressed; 1.5–2 mm long; indurate; shiny; without keel. Lemma margins involute. Lemma apex obtuse. Palea involute; indurate.

DISTRIBUTION North America: south-central USA. South America: Caribbean and Brazil.

NOTES Paniceae. Gr Texas 1994.

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