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.

Zea mexicana

HABIT Annual. Culms erect; 200–400 cm long; with prop roots. Culm-internodes solid. Leaves cauline. Ligule an eciliate membrane. Leaf-blades linear, or lanceolate; 60–120 cm long; 50–80 mm wide.

INFLORESCENCE Monoecious; with male and female spikelets in different inflorescences. Inflorescence composed of racemes; axillary; subtended by a spatheole; enclosed. Spatheole elliptic; herbaceous.

Racemes 1; single; bilateral. Rhachis fragile at the nodes; subcylindrical and excavated. Rhachis internodes inflated; 6–10 mm long. Rhachis internode tip oblique; flat.

Spikelets sunken; solitary. Fertile spikelets sessile. Male spikelets sessile and pedicelled; 2 in a cluster.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; laterally compressed; 4–8 mm long; falling entire; deciduous with accessory branch structures.

GLUMES Glumes dissimilar; reaching apex of florets; firmer than fertile lemma. Lower glume oblong; 1 length of spikelet; indurate; without keels. Upper glume elliptic; membranous; without keels.

FLORETS Basal sterile florets barren; with palea, or without significant palea. Lemma of lower sterile floret membranous. Fertile florets female. Fertile lemma elliptic; hyaline; without keel.

FLOWER Anthers 3. Stigmas 2; terminally exserted; papillose. Styles connate below.

FRUIT Caryopsis with adherent pericarp.

MALE Male inflorescence terminal; unlike female; of racemes along a central axis. Male spikelets distinct from female; with free pedicels; 2 flowered; elliptic; 7.5–10.5 mm long. Male spikelet glumes 2; wingless; muticous. Male spikelet lemma muticous.

DISTRIBUTION Africa: north. Asia-temperate: eastern Asia. Asia-tropical: Malesia. Australasia: Australia. North America: southwest USA, south-central USA, southeast USA, and Mexico.

NOTES Andropogoneae. WDC.

ADDITIONAL CHARACTERS Female internodes triangular; male lower glume convex.

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