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 alatum

HABIT Annual; caespitose. Culms erect, or geniculately ascending; 13–95 cm long. Culm-internodes terete; 1.5–10 cm long; distally glabrous, or hispid. Culm-nodes glabrous, or pubescent. Lateral branches ample; arising from lower culm. Leaf-sheaths 2–7 cm long; glabrous on surface, or hirsute; outer margin hairy. Ligule a ciliolate membrane; 0.7–1.8 mm long. Collar glabrous. Leaf-blades erect, or ascending; linear, or lanceolate; 2–18 cm long; 3–17 mm wide. Leaf-blade surface glabrous, or pilose; sparsely hairy; hairy abaxially. Leaf-blade margins scaberulous. Leaf-blade apex acute.

INFLORESCENCE Inflorescence a panicle. Peduncle 15–30 cm long.

Panicle open; pyramidal; effuse; 3.5–23 cm long; 1.5–11 cm wide. Panicle axis scaberulous; glabrous. Panicle branches scaberulous; glabrous.

Spikelets appressed; solitary. Fertile spikelets pedicelled. Pedicels clavate; 1–4 mm long; scaberulous; glabrous, or ciliate; hairy at tip.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic; dorsally compressed; acuminate; 2.4–3 mm long; 0.7–0.9 mm wide; falling entire. Rhachilla internodes elongated between glumes. Rhachilla elongation 0.5 mm long.

GLUMES Glumes dissimilar; reaching apex of florets; thinner than fertile lemma. Lower glume ovate; not clasping; 1.2–1.8 mm long; 0.5–0.75 length of spikelet; membranous; without keels; 5–7 -veined. Lower glume primary vein scaberulous. Lower glume apex acuminate. Upper glume elliptic; 2.2–2.7 mm long; 1 length of spikelet; membranous; without keels; 7–9(–11) -veined. Upper glume apex acute.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret similar to upper glume; elliptic; 2.1–2.8 mm long; 1 length of spikelet; membranous; 7–9(–11) -veined; acute. Fertile lemma obovate; thickened on margins at base; dorsally compressed; 1.5–1.8 mm long; 0.6–0.9 mm wide; indurate; grey; without keel. Lemma surface papillose. Lemma margins involute. Palea involute; indurate.

FLOWER Anthers 3; 1.3 mm long.

FRUIT Caryopsis with adherent pericarp; ovoid; 1–1.2 mm long; pallid. Embryo 0.5 length of caryopsis. Hilum punctiform.

DISTRIBUTION North America: Mexico. South America: western South America.

NOTES Paniceae. Zuloaga 2001.

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