Poaceae
Isachne

Isachne lutchuensis Hatus. & T.Koyama

First published in J. Jap. Bot. 31: 235 (1956)
This species is accepted
The native range of this species is Nansei-shotō (Iriomote-jima). It is an annual or perennial and grows primarily in the subtropical biome.

Descriptions

Morphology General Habit
Annual, or perennial; short-lived; caespitose; clumped loosely. Culms geniculately ascending; slender; 10-25 cm long; 0.5-0.8 mm diam.; rooting from lower nodes. Culm-internodes smooth; distally glabrous. Lateral branches sparse. Leaf-sheaths 1.5-3 cm long; mostly shorter than adjacent culm internode; glabrous on surface; outer margin glabrous. Leaf-sheath oral hairs scanty. Ligule a fringe of hairs. Leaf-blades lanceolate; 15-40 cm long; 3-7 mm wide; light green. Leaf-blade venation with 5-7 secondary veins. Leaf-blade surface glabrous. Leaf-blade margins unthickened; entire, or undulate. Leaf-blade apex acute.
Morphology Reproductive morphology Inflorescences
Inflorescence a panicle. Panicle open; ovate; 2-5 cm long; 2-5 cm wide. Primary panicle branches ascending, or spreading; 1 -nate; 1-4.5 cm long; bearing 4-12 fertile spikelets on each lower branch. Panicle axis 4-7 noded. Spikelets solitary. Fertile spikelets pedicelled. Pedicels filiform.
Morphology Reproductive morphology Inflorescences Spikelets
Spikelets comprising 2 fertile florets; without rhachilla extension. Spikelets orbicular, or obovate; dorsally compressed; 1-1.3 mm long; 0.8-1 mm wide; breaking up at maturity; disarticulating below each fertile floret.
Fertile
Spikelets comprising 2 fertile florets; without rhachilla extension. Spikelets orbicular, or obovate; dorsally compressed; 1-1.3 mm long; 0.8-1 mm wide; breaking up at maturity; disarticulating below each fertile floret.
Morphology Reproductive morphology Inflorescences Bracts Glume
Glumes deciduous; similar; shorter than spikelet; thinner than fertile lemma. Lower glume lanceolate, or ovate; 0.8-0.9 length of spikelet; membranous; much thinner on margins; without keels; 5-9 -veined. Lower glume surface hispid; hairy above. Lower glume apex obtuse, or acute. Upper glume lanceolate, or ovate; 0.8-0.9 length of spikelet; membranous; with hyaline margins; without keels; 5-9 -veined. Upper glume surface hispid; hairy above. Upper glume apex obtuse, or acute.
Morphology Reproductive morphology Flowers Florets
Fertile lemma elliptic, or ovate; 1-1.3 mm long; indurate; light green; without keel. Lemma lateral veins obscure. Lemma surface glabrous, or puberulous. Lemma margins involute. Lemma apex obtuse. Palea indurate; 2 -veined.
Morphology Reproductive morphology Fruits
Caryopsis with adherent pericarp.
Distribution
Asia-temperate: eastern Asia.
Reference
Isachneae. Gr Japan 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: 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

  • 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 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