Panicum tuerckheimii

HABIT Perennial. Rootstock evident. Culms erect, or geniculately ascending; 30–50 cm long. Culm-internodes elliptical in section; distally glabrous. Culm-nodes pubescent. Lateral branches lacking. Leaf-sheaths keeled; glabrous on surface. Ligule a ciliate membrane; 0.5 mm long. Leaf-blade base with a brief petiole-like connection to sheath. Leaf-blades lanceolate; 10–25 cm long; 20–25 mm wide. Leaf-blade margins ciliate; hairy at base. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence a panicle.

Panicle open; elliptic; 15–20 cm long. Primary panicle branches ascending; 5–10 cm long. Panicle axis glabrous. Panicle branches glabrous; 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; acuminate; 2.5–3 mm long; 0.9 mm wide; falling entire.

GLUMES Glumes dissimilar; shorter than spikelet; thinner than fertile lemma. Lower glume ovate; 0.05–0.1 length of spikelet; hyaline; without keels; 0 -veined. Lower glume lateral veins absent. Lower glume apex acute. Upper glume elliptic; 1 length of spikelet; membranous; dark brown; without keels. Upper glume lateral veins obscure. Upper glume surface puberulous. Upper glume apex acuminate.

FLORETS Basal sterile florets barren; with palea, or without significant palea. Lemma of lower sterile floret similar to upper glume; elliptic; 1 length of spikelet; membranous; light brown; obscurely veined; puberulous; acuminate. Fertile lemma elliptic; dorsally compressed; 2.4 mm long; 0.8 mm wide; coriaceous; without keel. Lemma margins involute. Lemma apex acute; pubescent. Palea involute; coriaceous.

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.