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 hirsutum

HABIT Perennial; caespitose. Culms 100–300 cm long; 5–10 mm diam.; compressible. Culm-nodes constricted; pubescent. Lateral branches sparse; arising from mid culm. Leaf-sheaths hispid; with tubercle-based hairs. Leaf-sheath oral hairs setose (behind ligule); erect. Ligule a ciliate membrane; 1.5–2 mm long. Collar bearded. Leaf-blade base cordate. Leaf-blades 35–70 cm long; 10–30 mm wide. Leaf-blade surface glabrous; hairless except near base (this hispid). Leaf-blade margins scabrous. Leaf-blade apex acute to acuminate.

INFLORESCENCE Inflorescence a panicle. Peduncle 10–22 cm long.

Panicle open; elliptic; dense; 15–50 cm long; 5–15 cm wide. Primary panicle branches ascending; whorled at lower nodes; 12–25 cm long; bearing spikelets almost to the base. Panicle branches scabrous.

Spikelets appressed; solitary. Fertile spikelets pedicelled. Pedicels 0.5–1.5 mm long.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets ovate; dorsally compressed; acute; 1.8–2.1 mm long; falling entire.

GLUMES Glumes dissimilar; reaching apex of florets; thinner than fertile lemma. Lower glume ovate; clasping; 0.9–1.2 mm long; 0.5 length of spikelet; membranous; without keels; 3 -veined. Lower glume apex acute. Upper glume ovate; 1.8–2.1 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; 1.8–2.1 mm long; 1 length of spikelet; membranous; 7–9 -veined; acute. Palea of lower sterile floret 0.66 length of lemma. Fertile lemma elliptic; dorsally compressed; 1.3–1.4 mm long; indurate; shiny; without keel. Lemma lateral veins distinct. Lemma margins involute. Palea involute; indurate.

FLOWER Anthers 3; 0.7 mm long; purple.

FRUIT Caryopsis with adherent pericarp; ellipsoid; 1 mm long; pallid.

DISTRIBUTION North America: south-central USA and Mexico. South America: Mesoamericana, Caribbean, northern South America, western South America, Brazil, and southern South America.

NOTES Paniceae. Fl Costa Rica 1994.

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