Poaceae
Hilaria

Hilaria jamesii (Torr.) Benth.

First published in J. Linn. Soc., Bot. 19: 62 (1881)
This species is accepted
The native range of this species is W. & Central U.S.A. It is a perennial 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]

Morphology General Habit
Perennial; caespitose. Rhizomes short. Culms erect; 20-65 cm long. Culm-internodes distally glabrous. Culm-nodes pubescent. Leaf-sheaths smooth, or scaberulous. Leaf-sheath oral hairs ciliate. Ligule an eciliate membrane; 2-3 mm long; lacerate. Leaf-blades involute; 2-20 cm long; 2-4 mm wide; stiff. Leaf-blade surface ribbed; scabrous; rough on both sides.
Morphology Reproductive morphology Inflorescences
Inflorescence composed of racemes. Racemes numerous; borne along a central axis; closely spaced; in a multilateral false spike; oblong; unilateral; 0.6-0.8 cm long; bearing a triad of spikelets. Central inflorescence axis 2-6 cm long; pubescent. Rhachis obsolete; deciduous from axis. Raceme-bases brief; pilose. Spikelets in threes. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 2 in the cluster.
Morphology Reproductive morphology Inflorescences Spikelets
Companion sterile spikelets well-developed; male; oblong; asymmetrical; dorsally compressed; 5-7 mm long; shorter than fertile; deciduous with the fertile. Companion sterile spikelet glumes free; membranous; 3-7 -veined; ciliolate on margins; lobed; 2 -fid; awned; one glume awned; with 6-8 mm long awn. Companion sterile spikelet lemmas 3; exserted from glumes; 5-7 mm long; muticous. Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets oblong; laterally compressed; 6-8 mm long; falling entire; deciduous with accessory branch structures.
Sterile
Companion sterile spikelets well-developed; male; oblong; asymmetrical; dorsally compressed; 5-7 mm long; shorter than fertile; deciduous with the fertile. Companion sterile spikelet glumes free; membranous; 3-7 -veined; ciliolate on margins; lobed; 2 -fid; awned; one glume awned; with 6-8 mm long awn. Companion sterile spikelet lemmas 3; exserted from glumes; 5-7 mm long; muticous.
Fertile
Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets oblong; laterally compressed; 6-8 mm long; falling entire; deciduous with accessory branch structures.
Morphology Reproductive morphology Inflorescences Bracts Glume
Glumes free; shorter than spikelet. Lower glume lanceolate; asymmetrical; chartaceous; pallid; 1-keeled; 7 -veined. Lower glume primary vein ciliate. Lower glume surface pubescent. Lower glume margins ciliate. Lower glume apex lobed; 5 -fid; awned; 7 -awned. Lower glume awn 3-5 mm long. Upper glume lanceolate; asymmetrical; 0.75 length of adjacent fertile lemma; chartaceous; pallid; 1-keeled; 7 -veined. Upper glume primary vein ciliate. Upper glume surface puberulous. Upper glume margins ciliate. Upper glume apex lobed; 5 -fid; awned; 7 -awned. Upper glume awn 3-5 mm long.
Morphology Reproductive morphology Flowers Florets
Fertile florets bisexual. Fertile lemma lanceolate; laterally compressed; 6-8 mm long; cartilaginous; keeled; 3 -veined. Lemma apex dentate; 2 -fid; obtuse; awned; 1 -awned. Principal lemma awn from a sinus; 2-3 mm long overall.
Morphology Reproductive morphology Flowers
Lodicules 2; 0.1-0.2 mm long. Anthers 3; 3 mm long.
Distribution
North America: northwest USA, southwest USA, and south-central USA.
Reference
Cynodonteae. Swallen.
[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

    • 'The Herbarium Catalogue, Royal Botanic Gardens, Kew. Published on the Internet http://www.kew.org/herbcat [accessed on Day Month Year]'. Please enter the date on which you consulted the system.
    • 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 2024. 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 2024. 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