Poaceae
Echinochloa

Echinochloa oplismenoides (E.Fourn.) Hitchc.

First published in Contr. U.S. Natl. Herb. 22: 136 (1920)
This species is accepted
The native range of this species is SE. Arizona to SW. New Mexico and Guatemala. It is an annual and grows primarily in the seasonally dry tropical biome.

Descriptions

Morphology General Habit
Annual; caespitose. Culms 50-100 cm long. Leaf-sheaths glabrous on surface. Ligule absent. Leaf-blades 10-25 cm long; 5-10 mm wide.
Morphology Reproductive morphology Inflorescences
Inflorescence composed of racemes. Racemes 5-15; borne along a central axis; appressed; unilateral; 2-5 cm long. Central inflorescence axis 10-15 cm long. Rhachis angular. Spikelet packing crowded; irregular; 2-4 -rowed. Spikelets in pairs. Fertile spikelets sessile and pedicelled; subequal. Pedicels oblong.
Morphology Reproductive morphology Inflorescences Spikelets
Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic; dorsally compressed; plano-convex; acuminate; 4-5 mm long; falling entire.
Fertile
Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic; dorsally compressed; plano-convex; acuminate; 4-5 mm long; falling entire.
Morphology Reproductive morphology Inflorescences Bracts Glume
Glumes dissimilar; reaching apex of florets; thinner than fertile lemma. Lower glume ovate; 2 mm long; 0.33-0.5 length of spikelet; without keels; 5 -veined. Lower glume surface scabrous. Lower glume apex cuspidate. Upper glume ovate; 1 length of spikelet; membranous; without keels; 5 -veined. Upper glume surface hispid. Upper glume apex cuspidate.
Morphology Reproductive morphology Flowers Florets
Basal sterile florets barren; with palea, or without significant palea. Lemma of lower sterile floret similar to upper glume; ovate; 1 length of spikelet; membranous; 5 -veined; hispid; acuminate; awned. Awn of lower sterile floret terminal; 8-16 mm long. Fertile lemma elliptic; gibbous; 4-4.5 mm long; 1.5-1.7 mm wide; indurate; without keel. Lemma margins involute. Lemma apex apiculate. Palea reflexed at apex; indurate.
Morphology Reproductive morphology Flowers
Anthers 3.
Distribution
North America: Mexico.
Reference
Paniceae. Fl Nov Gal 1997.
[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]

Sources

  • Angiosperm Extinction Risk Predictions v1

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

  • 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

  • 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 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