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 aztecanum

HABIT Perennial; caespitose. Culms erect; 50–100 cm long. Culm-internodes terete; 13–16 cm long. Culm-nodes glabrous. Leaf-sheaths 2–10 cm long; mostly shorter than adjacent culm internode; glabrous on surface, or pilose; outer margin glabrous. Leaf-sheath oral hairs ciliate; 2–3.6 mm long. Ligule a ciliate membrane; 0.4–0.6 mm long. Collar glabrous, or pubescent. Leaf-blades filiform, or linear; involute; 14–30 cm long; 1–3 mm wide. Leaf-blade surface pilose; sparsely hairy; hairy adaxially, or on both sides. Leaf-blade margins scaberulous. Leaf-blade apex acute.

INFLORESCENCE Inflorescence a panicle. Peduncle 25–48 cm long; glabrous.

Panicle open; pyramidal; effuse; 15–18 cm long; 8–10 cm wide. Panicle axis glabrous. Panicle branches glabrous in axils.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic; dorsally compressed; acute; 3.7–4.5 mm long; 1.5 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; 2–3 mm long; 0.5–0.75 length of spikelet; membranous; without keels; 7 -veined. Lower glume primary vein scaberulous. Lower glume apex acuminate. Upper glume elliptic; 3.2–4.2 mm long; 1 length of spikelet; membranous; without keels; 7–9 -veined. Upper glume apex acute.

FLORETS Basal sterile florets barren; with palea. Lemma of lower sterile floret similar to upper glume; elliptic; 3–4 mm long; 1 length of spikelet; membranous; 7–9 -veined; acute. Palea of lower sterile floret 1.7–2.7 mm long. Fertile lemma ovate; dorsally compressed; 2.4–3 mm long; 0.9–1.2 mm wide; indurate; yellow; shiny; without keel; 7 -veined. Lemma margins involute. Palea involute; indurate.

FLOWER Anthers 3; 1.3 mm long.

FRUIT Caryopsis with adherent pericarp; ovoid; 1.8 mm long; pallid. Embryo 0.5 length of caryopsis. Hilum punctiform.

DISTRIBUTION North America: Mexico.

NOTES Paniceae. Zuloaga 2001.

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