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 polycomum

HABIT Annual. Culms decumbent; 3–15 cm long; rooting from lower nodes. Culm-internodes distally glabrous. Culm-nodes purple; bearded. Lateral branches ample. Leaf-sheaths scaberulous; glabrous on surface, or hirsute; outer margin hairy. Ligule an eciliate membrane; 0.1–0.3 mm long. Collar glabrous. Leaf-blades flat, or conduplicate; 7–25 cm long; 1–2 mm wide. Leaf-blade surface glabrous, or hirsute; hairy adaxially, or on both sides. Leaf-blade margins glabrous, or tuberculate-ciliate.

INFLORESCENCE Inflorescence a panicle.

Panicle open; ovate; 1.2–2.5 cm long; 1–2 cm wide. Panicle branches smooth.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels filiform; flexuous.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic; dorsally compressed; 0.9–1.1 mm long; 0.3–0.5 mm wide; falling entire.

GLUMES Glumes reaching apex of florets; thinner than fertile lemma. Lower glume ovate; 0.5 mm long; 0.5 length of spikelet; membranous; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute. Upper glume ovate; 1 length of spikelet; membranous; without keels; 5 -veined. Upper glume surface glabrous, or pilose. Upper glume apex acute.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret similar to upper glume; ovate; 1 length of spikelet; membranous; 5 -veined; pilose; acute. Fertile lemma elliptic; dorsally compressed; 0.9–1 mm long; indurate; pallid; without keel. Lemma surface smooth. Lemma margins involute. Palea involute; indurate.

DISTRIBUTION South America: northern South America, western South America, and Brazil.

NOTES Paniceae. Fl Guiana 1995.

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