Poaceae
Orinus

Orinus thoroldii (Stapf ex Hemsl.) Bor

First published in Kew Bull. 6: 454 (1951 publ. 1952)
This species is accepted
The native range of this species is Central Asia to W. China and W. & Central Himalaya. It is a perennial or rhizomatous geophyte 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. Cataphylls evident. Rhizomes elongated. Culms erect; 30-50 cm long. Ligule an eciliate membrane; 1 mm long; lacerate. Leaf-blades flat, or involute; 10-15 cm long; 2-4 mm wide; glaucous. Leaf-blade surface ribbed; hirsute. Leaf-blade apex attenuate; hardened.
Morphology Reproductive morphology Inflorescences
Inflorescence composed of racemes. Racemes 4-8; borne along a central axis; deflexed to erect; unilateral; 1-7 cm long. Central inflorescence axis 7-15 cm long. Rhachis angular. Spikelet packing broadside to rhachis. Spikelets solitary. Fertile spikelets pedicelled. Pedicels oblong; 0.5-1 mm long; glabrous.
Morphology Reproductive morphology Inflorescences Spikelets
Spikelets comprising 2-3(-4) fertile florets; with diminished florets at the apex. Spikelets cuneate; laterally compressed; 7-9 mm long; breaking up at maturity; disarticulating below each fertile floret.
Fertile
Spikelets comprising 2-3(-4) fertile florets; with diminished florets at the apex. Spikelets cuneate; laterally compressed; 7-9 mm long; breaking up at maturity; disarticulating below each fertile floret.
Morphology Reproductive morphology Inflorescences Bracts Glume
Glumes persistent; similar; shorter than spikelet; thinner than fertile lemma. Lower glume lanceolate; 4-5 mm long; 0.8 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume primary vein scabrous. Lower glume lateral veins absent. Lower glume apex acute. Upper glume ovate; 5-6 mm long; 1 length of adjacent fertile lemma; membranous; without keels; 3 -veined. Upper glume surface scabrous; rough on veins. Upper glume margins eciliate, or ciliate. Upper glume apex acute.
Morphology Reproductive morphology Flowers Florets
Fertile lemma elliptic; 5.5-6 mm long; chartaceous; mid-green to black; keeled; 3 -veined. Lemma surface pilose; hairy all along; hairy on back. Lemma apex acute; muticous, or mucronate. Palea lanceolate; 0.8 length of lemma; 2 -veined. Palea keels ciliate. Palea surface pilose. Apical sterile florets resembling fertile though underdeveloped.
Morphology Reproductive morphology Flowers
Lodicules 2; cuneate; fleshy. Anthers 3; 2.5-2.75 mm long.
Morphology Reproductive morphology Fruits
Caryopsis with adherent pericarp; fusiform; isodiametric; biconvex; 2.5 mm long. Embryo 0.33 length of caryopsis. Hilum elliptic.
Distribution
Asia-temperate: China. Asia-tropical: India.
Reference
Eragrostideae. Bor.
[GB]

Morphology General Habit
Perennial. Rhizomes elongated; scaly. Culms erect; 15-35 cm long. Culm-internodes distally pilose. Leaf-sheaths pilose; outer margin hairy. Leaf-sheath oral hairs ciliate. Ligule an eciliate membrane; 1 mm long; lacerate. Leaf-blades linear, or lanceolate; 2-8 cm long; 2-4 mm wide. Leaf-blade surface ribbed; hirsute; hairy on both sides. Leaf-blade apex attenuate; hardened.
Morphology Reproductive morphology Inflorescences
Inflorescence composed of racemes. Racemes 4-8; borne along a central axis; unilateral; 3-5 cm long. Central inflorescence axis (3.5-)5-9 cm long. Rhachis angular. Spikelet packing broadside to rhachis. Spikelets solitary. Fertile spikelets pedicelled.
Morphology Reproductive morphology Inflorescences Spikelets
Spikelets comprising 5-8 fertile florets; with diminished florets at the apex. Spikelets cuneate; laterally compressed; 8-11 mm long; breaking up at maturity; disarticulating below each fertile floret.
Fertile
Spikelets comprising 5-8 fertile florets; with diminished florets at the apex. Spikelets cuneate; laterally compressed; 8-11 mm long; breaking up at maturity; disarticulating below each fertile floret.
Morphology Reproductive morphology Inflorescences Bracts Glume
Glumes persistent; similar; shorter than spikelet; thinner than fertile lemma. Lower glume lanceolate; 4.5-5.5 mm long; 0.9 length of upper glume; membranous; much thinner on margins; purple; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume surface glabrous, or pilose. Lower glume apex acute. Upper glume lanceolate; 5-6 mm long; 1 length of adjacent fertile lemma; membranous; with hyaline margins; purple; without keels; 3 -veined. Upper glume surface glabrous, or pilose. Upper glume apex acute.
Morphology Reproductive morphology Flowers Florets
Fertile lemma elliptic; 5-6 mm long; chartaceous; keeled; lightly keeled; 3 -veined. Lemma surface pilose; hairy all along; hairy on back. Lemma apex acute. Palea 2 -veined. Palea keels ciliate. Palea surface pubescent. Apical sterile florets resembling fertile though underdeveloped.
Morphology Reproductive morphology Flowers
Anthers 3; 3 mm long.
Morphology Reproductive morphology Fruits
Caryopsis with adherent pericarp; oblong.
Distribution
Asia-temperate: China.
Reference
Eragrostideae. Fl China 2005.
[GB]

Morphology General Habit
Perennial; caespitose; clumped loosely. Rhizomes elongated; scaly. Culms erect; 20-50 cm long; 1.5-2.5 mm diam.; 6-8 -noded. Culm-internodes distally pilose. Leaf-sheaths longer than adjacent culm internode; hirsute. Ligule an eciliate membrane; 1 mm long; lacerate. Leaf-blades 7-12 cm long; 2.5-4 mm wide. Leaf-blade surface hirsute; hairy on both sides.
Morphology Reproductive morphology Inflorescences
Inflorescence composed of racemes. Racemes 4-6; borne along a central axis; unilateral; 1-9 cm long. Central inflorescence axis 8-23 cm long. Spikelet packing broadside to rhachis. Spikelets solitary. Fertile spikelets pedicelled.
Morphology Reproductive morphology Inflorescences Spikelets
Spikelets comprising 3-4 fertile florets; with diminished florets at the apex. Spikelets lanceolate; laterally compressed; 7-9 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 1 mm long; glabrous.
Fertile
Spikelets comprising 3-4 fertile florets; with diminished florets at the apex. Spikelets lanceolate; laterally compressed; 7-9 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 1 mm long; glabrous.
Morphology Reproductive morphology Inflorescences Bracts Glume
Glumes persistent; similar; shorter than spikelet; thinner than fertile lemma. Lower glume linear; 6-7 mm long; 0.9 length of upper glume; membranous; much thinner on margins; 1-keeled; 1 -veined. Lower glume primary vein scabrous. Lower glume lateral veins absent. Lower glume apex acuminate. Upper glume lanceolate; 7-8.5 mm long; 1 length of adjacent fertile lemma; membranous; with hyaline margins; without keels; 3 -veined. Upper glume primary vein scaberulous. Upper glume apex acuminate.
Morphology Reproductive morphology Flowers Florets
Fertile lemma lanceolate; 6-7 mm long; chartaceous; keeled; lightly keeled; 3 -veined. Lemma surface villous; hairy all along. Lemma apex dentate; 3 -fid; acute. Palea 5-6 mm long; 2 -veined. Palea keels ciliate. Palea apex dentate; 2 -fid. Apical sterile florets resembling fertile though underdeveloped.
Morphology Reproductive morphology Flowers
Anthers 3; 3-3.5 mm long; yellow.
Morphology Reproductive morphology Fruits
Caryopsis with adherent pericarp; oblong; 2.5-3 mm long; light brown.
Distribution
Asia-temperate: China.
Reference
Eragrostideae. Cai & Su 2011.
[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 2025. 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 2025. 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