Panicum cayennense

HABIT Annual; caespitose. Culms erect, or geniculately ascending; 18–40 cm long; 1–2 mm diam. Culm-internodes distally glabrous, or hispid; with tubercle-based hairs. Lateral branches ample; arising from lower culm and mid culm. Leaf-sheaths hispid; with tubercle-based hairs. Ligule a ciliate membrane; 0.8–1.2 mm long. Leaf-blades 9–13 cm long; 5–8 mm wide. Leaf-blade surface pilose; with tubercle-based hairs.

INFLORESCENCE Inflorescence a panicle; terminal and axillary. Axillary inflorescences intermingled with terminal.

Panicle open; ovate; 5–16 cm long; 4–8 cm wide. Primary panicle branches branching divaricately. Panicle branches scabrous; pubescent in axils.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets obovate; dorsally compressed; cuspidate; 2.1–2.3 mm long; falling entire. Rhachilla internodes elongated between glumes. Rhachilla elongation 0.4 mm long.

GLUMES Glumes dissimilar; reaching apex of florets; thinner than fertile lemma. Lower glume ovate; 1.3–1.6 mm long; 0.6–0.7 length of spikelet; membranous; without keels; 5 -veined. Lower glume apex acute. Upper glume ovate; 1.8–2 mm long; 1 length of spikelet; membranous; without keels; 7 -veined. Upper glume apex acute.

FLORETS Basal sterile florets barren; with palea. Lemma of lower sterile floret similar to upper glume; ovate; 1.8–2 mm long; 1 length of spikelet; membranous; 5 -veined; acute. Palea of lower sterile floret 0.75–0.8 length of lemma. Fertile lemma elliptic; dorsally compressed; 1.4–1.5 mm long; indurate; shiny; without keel. Lemma margins involute. Palea involute; indurate.

FLOWER Anthers 3; 0.7–0.9 mm long; purple.

DISTRIBUTION North America: Mexico. South America: Mesoamericana, Caribbean, northern South America, western South America, and Brazil.

NOTES Paniceae. Fl Costa Rica 1994.

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