Poaceae
Arthraxon

Arthraxon hispidus (Thunb.) Makino

First published in Bot. Mag. (Tokyo) 26: 214 (1912)
This species is accepted
The native range of this species is Tropical Africa, W. Indian Ocean, Asia to E. Australia. It is an annual or perennial and grows primarily in the seasonally dry tropical biome.

Descriptions

Morphology General Habit
Annual; mat forming. Culms rambling; slender; 7-60(-100) cm long; 0.3-1 mm diam.; rooting from lower nodes. Culm-internodes 1-6 cm long. Culm-nodes pubescent. Leaf-sheaths glabrous on surface, or pilose, or hispid; with tubercle-based hairs; outer margin glabrous, or hairy. Ligule a ciliolate membrane; 0.5-3 mm long. Leaf-blade base amplexicaul. Leaf-blades lanceolate, or ovate; 1-8 cm long; 3-25 mm wide. Leaf-blade surface glabrous, or pilose; sparsely hairy; hairy on both sides. Leaf-blade margins tuberculate-ciliate; hairy all along, or at base. Leaf-blade apex acute.
Morphology Reproductive morphology Inflorescences
Inflorescence composed of racemes. Racemes 2-50; digitate; 1.5-5 cm long. Rhachis fragile at the nodes; glabrous on margins, or ciliate on margins. Rhachis hairs (0.5-)0.66-0.75 mm long. Rhachis internodes filiform to linear; 2-6 mm long. Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels linear; 0.1-2 mm long; glabrous, or ciliate.
Sterile
Companion sterile spikelets represented by barren pedicels.
Morphology Reproductive morphology Inflorescences Spikelets
Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; 3-8 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus glabrous, or pubescent; base truncate; attached transversely. Companion sterile spikelets represented by barren pedicels.
Fertile
Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; 3-8 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus glabrous, or 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; chartaceous; much thinner on margins; without keels; 7-9 -veined. Lower glume surface convex; spinose; rough on veins. Lower glume apex obtuse. Upper glume lanceolate; chartaceous; 1-keeled; keeled above; 3-5 -veined. Upper glume primary vein scaberulous. Upper glume apex acute, or obtuse.
Morphology Reproductive morphology Flowers Florets
Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; 0.66 length of spikelet; hyaline; 2 -veined; obtuse. Fertile lemma oblong; 2-6 mm long; hyaline; without keel; 1 -veined. Lemma apex acute; muticous, or awned; 1 -awned. Principal lemma awn dorsal; arising 0.2 way up back of lemma; geniculate; 0-20 mm long overall; with a straight or slightly twisted column, or with twisted column. Column of lemma awn glabrous. Palea absent or minute.
Morphology Reproductive morphology Flowers
Anthers 2; 0.5-1 mm long.
Morphology Reproductive morphology Fruits
Caryopsis with adherent pericarp; fusiform, or oblong; 3.5-5 mm long.
Distribution
Africa: west tropical, west-central tropical, northeast tropical, east tropical, southern tropical, and western Indian ocean. Asia-temperate: Soviet far east, Soviet Middle Asia, Caucasus, western Asia, Arabia, China, Mongolia, and eastern Asia. Asia-tropical: India, Indo-China, Malesia, and Papuasia. Australasia: Australia. Pacific: north-central. North America: north-central USA, northeast USA, southeast USA, and Mexico. South America: Mesoamericana, Caribbean, northern South America, and western South America.
Reference
Andropogoneae. Fl China 2005.
[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: not 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 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