Acrachne racemosa (B.Heyne ex Roth) Ohwi

First published in Bull. Tokyo Sci. Mus. 18: 1 (1947)
This species is accepted
The native range of this species is Tropical & Subtropical Old World to N. Australia. It is an annual and grows primarily in the seasonally dry tropical biome.

Descriptions

Gramineae, T. Cope. Flora Zambesiaca 10:2. 1999

Morphology General Habit
Caespitose annual; culms up to 75 cm tall, slender erect or geniculately ascending; leaf laminas 7–20 cm × 5–11.5 mm, soft, rounded at the base, tapering to a fine hair-like apex.
Morphology Reproductive morphology Inflorescences
Racemes 1.5–10 cm long, ascending, mainly grouped in whorls of 2–5 and either clustered subdigitately towards the top of the culm or arranged along a central axis up to 15 cm long.
Morphology Reproductive morphology Inflorescences Spikelets
Spikelets 5.5–13 mm long; glumes unequal, the inferior 1.2–2.9 mm long, linear-oblong in profile, acute and mucronate at the apex, the superior 1.5–3 mm long, lanceolate in profile, acuminate and awned at the apex, the awn 1/3–2/3 as long as the body; lemmas 2.1–2.8 mm long, narrowly ovate in profile, the keel scabrid and shallowly concave above the middle, the mid-nerve excurrent into a stout awn-point 0.3–0.9 mm long.
[FZ]

Gramineae, W. D. Clayton. Flora of West Tropical Africa 3:2. 1972

Morphology General Habit
Annual 30–60 cm. high
Ecology
Disturbed soils.
[FWTA]

Morphology General Habit
Annual; caespitose. Basal innovations intravaginal. Culms geniculately ascending, or decumbent; 15-75 cm long; 1-3 mm diam.; 2-5 -noded. Lateral branches sparse. Leaves cauline. Leaf-sheaths as wide as blade at the collar; keeled. Ligule a ciliolate membrane; 0.5-1.25 mm long. Leaf-blades 15-75 cm long; 5-11.5 mm wide. Leaf-blade surface smooth; glabrous, or pilose; sparsely hairy. Leaf-blade margins cartilaginous. Leaf-blade apex attenuate; filiform.
Morphology Reproductive morphology Inflorescences
Inflorescence composed of racemes. Racemes 3-25; digitate, or borne along a central axis; in several whorls; unilateral; 1.5-10 cm long. Central inflorescence axis 0-15 cm long. Rhachis angular; terminating in a sterile spikelet. Spikelet packing broadside to rhachis; regular; 2 -rowed. Spikelets appressed; solitary, or in pairs. Fertile spikelets sessile; 1-2 in the cluster.
Sterile
Apical sterile spikelets rudimentary; 1 in number.
Morphology Reproductive morphology Inflorescences Spikelets
Spikelets comprising 6-25 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 5.5-13 mm long; 2.5-3 mm wide; breaking up at maturity; rhachilla persistent; retaining paleas; tough throughout, or fragile above; with the distal florets falling as a whole. Rhachilla internodes 0.1 mm long; eventually visible between lemmas. Apical sterile spikelets rudimentary; 1 in number.
Fertile
Spikelets comprising 6-25 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 5.5-13 mm long; 2.5-3 mm wide; breaking up at maturity; rhachilla persistent; retaining paleas; tough throughout, or fragile above; with the distal florets falling as a whole. Rhachilla internodes 0.1 mm long; eventually visible between lemmas.
Morphology Reproductive morphology Inflorescences Bracts Glume
Glumes deciduous; similar; shorter than spikelet. Lower glume lanceolate; 1.2-2.9 mm long; 0.5-0.8 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume apex acuminate; mucronate. Upper glume ovate; 1.5-3 mm long; 0.5-0.7 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume primary vein scabrous. Upper glume lateral veins absent. Upper glume apex entire; acuminate; mucronate.
Morphology Reproductive morphology Flowers Florets
Fertile florets recurved at tip. Fertile lemma ovate; laterally compressed; ovate in profile; 2.1-2.8 mm long; membranous; yellow to mid-green; keeled; 3 -veined. Lemma midvein scaberulous. Lemma lateral veins excurrent. Lemma apex entire; acute; awned; 1 -awned. Principal lemma awn 0.3-0.9 mm long overall. Palea ovate; bowed outwards; 0.8 length of lemma; 2 -veined. Palea keels scabrous. Palea apex dentate; 2 -fid; acute. Apical sterile florets resembling fertile though underdeveloped.
Morphology Reproductive morphology Flowers
Lodicules 2; cuneate; fleshy. Anthers 3; 0.4 mm long. Stigmas 2; protandrous; laterally exserted.
Morphology Reproductive morphology Fruits
Caryopsis with free soft pericarp; ellipsoid; isodiametric; biconvex; estipitate; sulcate on hilar side; 0.8-1 mm long; rugose; apex unappendaged. Embryo 0.4 length of caryopsis. Hilum punctiform. Endosperm farinose. Disseminule comprising a caryopsis.
Distribution
Africa: north, Macaronesia, west tropical, west-central tropical, northeast tropical, east tropical, southern tropical, and south. Asia-temperate: western Asia, Arabia, and China. Asia-tropical: India and Indo-China. Australasia: Australia. South America: Caribbean.
Reference
Eragrostideae. WDC.
[GB]

M. Thulin et al. Flora of Somalia Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Morphology Stem
Stems up to 75 cm high
Morphology Reproductive morphology Inflorescences
Racemes digitate, often with additional whorls below, 1.5–10 cm long
Morphology Reproductive morphology Inflorescences Spikelets
Spikelets 6- to 25-flowered, 5.5–13 mm long; glumes unequal, the lower 1.2–3 mm long, acute and mucronate, the upper 1.5–3 mm long, acuminate and awned, the awn 1/3–2/3 the length of the body; lemmas narrowly ovate in profile, 2–2.8 mm long, the awn 0.3–0.9 mm long.
Distribution
N1; S1, 2 Old World tropics.
Vernacular
Dhalad (Somali)
[FSOM]

Gramineae, W. D. Clayton, S. M. Phillips & S. A. Renvoize. Flora of Tropical East Africa. 1974

Morphology General Habit
Tufted annual; culms 15–75 cm. high, moderately slender, erect or geniculately ascending.
Morphology Leaves
Leaf-blades 7–20 cm. long, 5–11.5 mm. wide, soft, glabrous or sparsely pilose on the upper surface, rounded at the base, tapering to a fine hair-like tip; ligule 1.25 mm. long.
Morphology Reproductive morphology Inflorescences
Inflorescence composed of several-many slender ascending secund spikes 1.5–10 cm. long, these mainly grouped in whorls of 2–5 and either clustered subdigitately towards the top of the culm or arranged along a central axis up to 15 cm. long.
Morphology Reproductive morphology Inflorescences Spikelets
Spikelets 6–25-flowered, 5.5–13 mm. long, closely overlapping, whitish green or brownish; glumes unequal, the lower linear-oblong in profile, 1.2–2.9 mm. long, acute and mucronate, the upper lanceolate in profile, 1.5–3 mm. long, acuminate and awned, the awn 1/3–2/3 as long as the glume; lemmas narrowly ovate in profile, 2.1–2.8 mm. long, scabrid on the upper part of the keel, this shallowly concave above the middle and excurrent into a stout awn-point 0.3–0.9 mm. long.
Morphology Reproductive morphology Fruits
Grain blackish, oblong, 0.8–1.1 mm. long, rugose, the surface finely and densely granular.
Figures
Fig. 71, p. 259.
Habitat
Deciduous bushland; 470–1700 m.
Distribution
K1 K3 K4 K6 K7 T3 Africa from Senegal eastwards to Eritrea, and southwards to South West Africa and TransvaalOld World tropics, including Australia
[FTEA]

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

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    • Angiosperm Threat Predictions
    • http://creativecommons.org/licenses/by/4.0
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    • Flora Zambesiaca
    • http://creativecommons.org/licenses/by-nc-sa/3.0
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    • Flora of Somalia
    • http://creativecommons.org/licenses/by-nc-sa/3.0
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    • Flora of Tropical East Africa
    • http://creativecommons.org/licenses/by-nc-sa/3.0
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    • Flora of West Tropical Africa
    • http://creativecommons.org/licenses/by-nc-sa/3.0
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    • 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
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    • 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