Panicum stramineum

HABIT Annual. Culms geniculately ascending; 20–50 cm long. Culm-internodes distally glabrous. Culm-nodes pubescent. Lateral branches sparse. Leaf-sheaths smooth, or papillose; glabrous on surface, or pilose; with tubercle-based hairs. Ligule a ciliate membrane. Leaf-blade base broadly rounded, or cordate. Leaf-blades appressed, or erect; 10–30 cm long; 4–15 mm wide. Leaf-blade surface smooth to scabrous; rough adaxially; glabrous. Leaf-blade margins scabrous; glabrous, or ciliate; hairy at base.

INFLORESCENCE Inflorescence a panicle.

Panicle open; ovate; 5–15 cm long; 0.25–0.33 of culm length.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic; dorsally compressed; compressed slightly; acuminate; 3.2–3.7 mm long; 1.5 mm wide; falling entire.

GLUMES Glumes dissimilar; reaching apex of florets; thinner than fertile lemma. Lower glume ovate; 0.33 length of spikelet; membranous; without keels; 5 -veined. Lower glume apex obtuse, or acute. Upper glume elliptic; 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; elliptic; 1 length of spikelet; membranous; 7 -veined; acute. Palea of lower sterile floret 1 length of lemma. Fertile lemma elliptic, or obovate; dorsally compressed; 2.2 mm long; indurate; pallid; without keel. Lemma margins involute. Lemma apex obtuse. Palea involute; indurate.

DISTRIBUTION North America: southwest USA and Mexico. South America: western South America and Brazil.

NOTES Paniceae. Chase 1994.

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