Poaceae
Zea

Zea mexicana (Schrad.) Kuntze

First published in T.E.von Post & C.E.O.Kuntze, Lex. Gen. Phan.: 599 (1904)
This species is accepted
The native range of this species is Mexico (Chihuahua to N. Oaxaca). It is an annual and grows primarily in the seasonally dry tropical biome.

Descriptions

Morphology General 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.
Morphology Reproductive morphology Inflorescences
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. 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.
Morphology Reproductive morphology Inflorescences 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.
Fertile
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.
Morphology Reproductive morphology Inflorescences Bracts Glume
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.
Morphology Reproductive morphology Flowers 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.
Morphology Reproductive morphology Flowers
Anthers 3. Stigmas 2; terminally exserted; papillose. Styles connate below.
Morphology Reproductive morphology Fruits
Caryopsis with adherent pericarp.
sex 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.
Reference
Andropogoneae. WDC.
Diagnostic
Female internodes triangular; male lower glume convex.
[GB]

Extinction risk predictions for the world's flowering plants to support their conservation (2024). Bachman, S.P., Brown, M.J.M., Leão, T.C.C., Lughadha, E.N., Walker, B.E. https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.19592

Conservation
Predicted extinction risk: not threatened. Confidence: confident
[AERP]

Common Names

english
annual teosinte
unknown
rynia, teosinte

Sources

  • Angiosperm Extinction Risk Predictions v1

    • Angiosperm Threat Predictions
    • http://creativecommons.org/licenses/by/4.0

  • EBC Common Names

    • Common Names from Kew's Economic Botany Collection https://www.kew.org/science/collections-and-resources/collections/economic-botany-collection

  • GrassBase - The Online World Grass Flora

    • Clayton, W.D., Vorontsova, M.S., Harman, K.T. and Williamson, H. (2006 onwards). GrassBase - The Online World Grass Flora.
    • http://creativecommons.org/licenses/by-nc-sa/3.0

  • Herbarium Catalogue Specimens

    • Digital Image © Board of Trustees, RBG Kew http://creativecommons.org/licenses/by/3.0/

  • Kew Backbone Distributions

    • The International Plant Names Index and World Checklist of Vascular Plants 2026. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0

  • Kew Living Collection Database

    • Common Names from Kew's Living Collection Database

  • Kew Names and Taxonomic Backbone

    • The International Plant Names Index and World Checklist of Vascular Plants 2026. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 International Plant Names Index and World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0