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 diploperennis

HABIT Perennial; caespitose. Rhizomes short (internodes 0.2–0.6cm); scaly. Culms erect; robust; 100–250 cm long; 10–20 mm diam. Culm-internodes solid. Leaves cauline. Ligule an eciliate membrane; 1–2 mm long. Leaf-blade base cordate. Leaf-blades linear, or lanceolate; 40–80 cm long; 40–50 mm wide. Leaf-blade surface glabrous.

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; bearing 5–10 fertile spikelets on each. Rhachis fragile at the nodes; subcylindrical and excavated. Rhachis internodes inflated; 6–8.2 mm long. Rhachis internode tip oblique; flat.

Spikelets sunken; solitary. Fertile spikelets sessile. Male spikelets sessile, or sessile and pedicelled; 2 in a cluster. Pedicels (male) 1.5–3 mm long.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; laterally compressed; 4–6 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 subdigitate racemes, or of racemes along a central axis. Male spikelets distinct from female; with free pedicels; 2 flowered; elliptic; 8.5–11.5 mm long. Male spikelet glumes 2; winged; muticous. Male spikelet lemma muticous.

DISTRIBUTION North America: Mexico.

NOTES Andropogoneae. Iltis 1993.

ADDITIONAL CHARACTERS Female internodes trapezoidal; male lower glume flat.

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