Panicum amarum

HABIT Perennial; culms solitary, or caespitose. Rhizomes elongated. Culms erect; 30–200 cm long. Culm-internodes glaucous; distally glabrous. Leaf-sheaths without keel. Ligule a ciliate membrane; 2–3.5 mm long. Leaf-blades flat, or conduplicate; 10–50 cm long; 3–15 mm wide; glaucous. Leaf-blade surface glabrous. Leaf-blade margins smooth.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; lanceolate; 10–35 cm long; 3–10 cm wide; 0.25–0.33 of culm length. Primary panicle branches appressed. Panicle branches glabrous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels glabrous.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets ovate; dorsally compressed; acuminate; 4.5–6 mm long; falling entire.

GLUMES Glumes dissimilar; reaching apex of florets; thinner than fertile lemma. Lower glume ovate; 0.5–0.66 length of spikelet; membranous; without keels; 5–7 -veined. Lower glume apex acute. Upper glume elliptic; 1 length of spikelet; membranous; without keels; 7 -veined. Upper glume apex acuminate.

FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret similar to upper glume; elliptic; 1 length of spikelet; membranous; 5 -veined; acuminate. Fertile lemma oblong, or ovate; dorsally compressed; 3–3.5 mm long; indurate; shiny; without keel. Lemma margins involute. Lemma apex obtuse. Palea involute; indurate.

DISTRIBUTION North America: northeast 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.