Poaceae
Arthraxon

Arthraxon raizadae S.K.Jain, Hemadri & Deshp.

First published in J. Indian Bot. Soc. 51: 103 (1972)
This species is accepted
The native range of this species is India. It is an annual and grows primarily in the seasonally dry tropical biome.

Descriptions

Morphology General Habit
Annual. Culms geniculately ascending, or decumbent; 10-50 cm long; rooting from lower nodes. Lateral branches sparse. Leaf-sheaths 1-2 cm long; striately veined; glabrous on surface, or pilose; outer margin hairy. Ligule a ciliolate membrane; 1.5 mm long. Leaf-blade base cordate. Leaf-blades lanceolate, or ovate; 2-7 cm long; 4-20 mm wide. Leaf-blade surface pilose; sparsely hairy; with tubercle-based hairs. Leaf-blade margins tuberculate-ciliate. Leaf-blade apex acuminate.
Morphology Reproductive morphology Inflorescences
Inflorescence composed of racemes. Peduncle 6-12 cm long. Racemes 1-2; single, or paired; 2-5 cm long. Rhachis fragile at the nodes; ciliate on margins. Rhachis internodes linear; 3.5-4.5 mm long. Rhachis internode tip not enlarged. Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels filiform; 2.5 mm long; ciliate; hairy all along but hairs longer above.
Morphology Reproductive morphology Inflorescences Spikelets
Companion sterile spikelets well-developed; male; lanceolate; dorsally compressed; 5 mm long; shorter than fertile. Companion sterile spikelet glumes chartaceous; 4-5 mm long; keeled; 6-7 -veined. Companion sterile spikelet lemmas 2; enclosed by glumes; 3.5-4 mm long. Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 6-7 mm long; 1-1.3 mm wide; falling entire; deciduous with accessory branch structures. Spikelet callus square; 0.5 mm long; pubescent; base truncate; attached transversely.
Sterile
Companion sterile spikelets well-developed; male; lanceolate; dorsally compressed; 5 mm long; shorter than fertile. Companion sterile spikelet glumes chartaceous; 4-5 mm long; keeled; 6-7 -veined. Companion sterile spikelet lemmas 2; enclosed by glumes; 3.5-4 mm long.
Fertile
Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 6-7 mm long; 1-1.3 mm wide; falling entire; deciduous with accessory branch structures. Spikelet callus square; 0.5 mm long; pubescent; base truncate; attached transversely.
Morphology Reproductive morphology Inflorescences Bracts Glume
Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate; 1 length of spikelet; coriaceous; 2-keeled. Lower glume primary vein scabrous. Lower glume surface pubescent. Lower glume margins ciliate. Upper glume lanceolate; chartaceous; 1-keeled; keeled above. Upper glume primary vein ciliolate. Upper glume surface pilose; hairy at apex.
Morphology Reproductive morphology Flowers Florets
Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; 3-4 mm long; hyaline; obtuse. Fertile lemma lanceolate; 5 mm long; hyaline; without keel. Lemma apex acute; awned; 1 -awned. Principal lemma awn dorsal; arising 0.1 way up back of lemma; geniculate; 15-17.5 mm long overall; with twisted column. Palea absent or minute.
Morphology Reproductive morphology Flowers
Anthers 3; 2-3 mm long.
Morphology Reproductive morphology Fruits
Caryopsis with adherent pericarp; linear; isodiametric; dark brown.
Distribution
Asia-tropical: India.
Reference
Andropogoneae. Jain 1999.
[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

    • '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