Poaceae
Hordeum

Hordeum pusillum Nutt.

First published in Gen. N. Amer. Pl. 1: 87 (1818)
This species is accepted
The native range of this species is W. Canada to N. Mexico, Bermuda, Argentina. It is an annual and grows primarily in the temperate biome.

Descriptions

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]

IUCN Red List of Threatened Species https://www.iucnredlist.org/species/21345256/21413380

Conservation
LC - least concern
[IUCN]

Morphology General Habit
Perennial; caespitose. Culms geniculately ascending; 10-40 cm long. Culm-nodes brown; glabrous. Leaf-sheaths glabrous on surface, or pubescent. Leaf-sheath auricles absent, or falcate. Ligule an eciliate membrane; 0.5 mm long; truncate. Leaf-blades 3-12 cm long; 2-4 mm wide. Leaf-blade surface glabrous, or pubescent.
Morphology Reproductive morphology Inflorescences
Inflorescence composed of racemes. Racemes 1; single; linear; bilateral; 4-8 cm long; 4-8 mm wide. Rhachis fragile at the nodes; flattened. Spikelet packing broadside to rhachis. Rhachis internodes oblong; falling with spikelet above. Spikelets in threes. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 2 in the cluster. Pedicels oblong.
Morphology Reproductive morphology Inflorescences Spikelets
Companion sterile spikelets well-developed; containing empty lemmas, or male; linear; as long as fertile; deciduous with the fertile. Companion sterile spikelet glumes subulate; 8-15 mm long. Companion sterile spikelet lemmas 1; 1.5-3 mm long; 1-awned; with 1-2 mm long awn. Spikelets comprising 1 fertile florets; with a barren rhachilla extension. Spikelets lanceolate; dorsally compressed; 4-6 mm long; falling entire; deciduous with accessory branch structures.
Sterile
Companion sterile spikelets well-developed; containing empty lemmas, or male; linear; as long as fertile; deciduous with the fertile. Companion sterile spikelet glumes subulate; 8-15 mm long. Companion sterile spikelet lemmas 1; 1.5-3 mm long; 1-awned; with 1-2 mm long awn.
Fertile
Spikelets comprising 1 fertile florets; with a barren rhachilla extension. Spikelets lanceolate; dorsally compressed; 4-6 mm long; falling entire; deciduous with accessory branch structures.
Morphology Reproductive morphology Inflorescences Bracts Glume
Glumes collateral; similar; shorter than spikelet; gaping. Lower glume subulate; 7-15 mm long; 1 length of upper glume. Upper glume subulate; 7-15 mm long.
Morphology Reproductive morphology Flowers Florets
Fertile lemma lanceolate; 4-6 mm long; coriaceous; without keel; 5 -veined. Lemma surface scabrous. Lemma apex acuminate; awned; 1 -awned. Principal lemma awn 2-7 mm long overall.
Morphology Reproductive morphology Flowers
Anthers 3. Ovary pubescent on apex.
Morphology Reproductive morphology Fruits
Caryopsis with adherent pericarp; hairy at apex. Hilum linear.
Distribution
North America: western Canada, eastern Canada, northwest USA, north-central USA, northeast USA, southwest USA, south-central USA, southeast USA, and Mexico. South America: Caribbean, Brazil, and southern South America.
Reference
Triticeae. Gr Texas 1994.
[GB]

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

  • Herbarium Catalogue Specimens

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

  • IUCN Categories

    • IUCN Red List of Threatened Species
    • 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