GrassBase - The Online World Grass Flora

Descriptions

W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Panicum stagnatile

HABIT Perennial. Culms decumbent; 100–200 cm long; 4–5 mm diam.; rooting from lower nodes. Culm-internodes elliptical in section; 12–20 cm long. Culm-nodes glabrous, or pubescent. Lateral branches lacking, or sparse. Leaf-sheaths striately veined; glabrous on surface; outer margin hairy. Leaf-sheath oral hairs ciliate. Ligule a ciliolate membrane; 0.8 mm long. Leaf-blade base broadly rounded, or cordate. Leaf-blades lanceolate; 22–35 cm long; 15–30 mm wide. Leaf-blade surface pubescent; hairy adaxially. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence a panicle.

Panicle open; pyramidal; 20–40 cm long; contracted about secondary branches. Primary panicle branches ascending, or spreading; 1–2 cm long; bearing spikelets almost to the base. Panicle axis scabrous. Panicle branches angular; secund; pubescent in axils.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 1.6–1.8 mm long; 0.4–0.5 mm wide; falling entire.

GLUMES Glumes dissimilar; shorter than spikelet; thinner than fertile lemma. Lower glume ovate; 0.6–0.9 mm long; 0.33–0.5 length of spikelet; membranous; 1-keeled; 1–3 -veined. Lower glume primary vein scaberulous. Lower glume apex acute. Upper glume elliptic; 0.9 length of spikelet; membranous; without keels; 3(–5) -veined. Upper glume surface scabrous. Upper glume apex obtuse, or acute.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret similar to upper glume; elliptic; 1 length of spikelet; membranous; 3 -veined; scabrous; acute. Fertile lemma elliptic; dorsally compressed; 1.5 mm long; 0.4 mm wide; chartaceous; pallid; without keel. Lemma margins flat (above), or involute (below). Lemma apex acute. Palea involute; chartaceous.

FLOWER Anthers 0.4–0.8 mm long.

DISTRIBUTION North America: Mexico. South America: Mesoamericana.

NOTES Paniceae. Chase 1994.

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