Panicum longifolium

HABIT Perennial; caespitose. Culms erect, or geniculately ascending; 40–100 cm long. Culm-internodes elliptical in section. Culm-nodes glabrous. Lateral branches lacking, or sparse; arising from upper culm. Leaf-sheaths keeled; glabrous on surface, or hispid. Ligule a fringe of hairs; 0.5–1 mm long. Collar glabrous, or pubescent. Leaf-blades flat, or conduplicate; 25–50 cm long; 4–12 mm wide. Leaf-blade surface glabrous, or hispid; sparsely hairy.

INFLORESCENCE Inflorescence a panicle; terminal and axillary.

Panicle open, or contracted; lanceolate, or ovate; 10–40 cm long; contracted about secondary branches. Primary panicle branches ascending. Panicle branches with scattered hairs.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels bearing a few hairs.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic; dorsally compressed; acute; 1.6–2.5 mm long; falling entire. Floret callus brief, or evident.

GLUMES Glumes dissimilar; reaching apex of florets; thinner than fertile lemma. Lower glume ovate; 0.6–0.7 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; 1.2–2 mm long; indurate; shiny; without keel. Lemma margins involute. Lemma apex laterally pinched. Palea involute; indurate.

DISTRIBUTION North America: western Canada, eastern Canada, north-central USA, northeast USA, southwest USA, south-central USA, southeast USA, and Mexico. South America: Mesoamericana and Caribbean.

NOTES Paniceae. Gr Texas 1994.

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