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.

Axonopus pressus

HABIT Perennial. Rhizomes elongated; not obviously scaly, or scaly. Culms robust; 80–120 cm long; 2–4 -noded. Culm-internodes elliptical in section. Culm-nodes glabrous. Lateral branches lacking. Leaf-sheaths 10–40 cm long; outer margin hairy. Ligule a ciliolate membrane; 0.4–0.8 mm long. Leaf-blades erect, or spreading; conduplicate; 10–30 cm long; 5–12 mm wide; stiff. Leaf-blade surface scabrous; glabrous, or hirsute. Leaf-blade apex obtuse.

INFLORESCENCE Inflorescence composed of racemes; with 1 peduncles per sheath. Peduncle 20–50 cm long; smooth, or scaberulous above.

Racemes 4–30; digitate; ascending, or spreading; unilateral; 10–30 cm long. Central inflorescence axis 5–7 cm long. Rhachis angular; 0.5–0.8 mm wide; drab; glabrous on surface; scabrous on margins; glabrous on margins. Spikelet packing adaxial; 5.5–7 spikelets per cm. Raceme-bases brief; pubescent.

Spikelets appressed; solitary. Fertile spikelets pedicelled. Pedicels reduced to a stump; 0.2–0.5 mm long; glabrous.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong, or ovate; dorsally compressed; obtuse, or subacute; 2.2–2.7 mm long; 0.8–0.9 mm wide; falling entire.

GLUMES Glumes one the lower absent or obscure; reaching apex of florets; thinner than fertile lemma. Upper glume 1 length of spikelet; membranous; 2 -veined. Upper glume primary vein absent.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret similar to upper glume; 1 length of fertile lemma; 1 length of spikelet; 2 -veined; without midvein. Fertile lemma 2.2–2.7 mm long; indurate; dark brown; shiny; without keel. Lemma margins involute. Lemma apex without ornament. Palea involute; indurate.

FRUIT Caryopsis with adherent pericarp.

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

NOTES Paniceae. Black 1994.

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