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EPPO ACQAM
Species Acroceras amplectens
Author Stapf.
Family Poaceae
Weed Type Grass
General Habit Annual or perennial herbs, or tall woody bamboos.
Stem Jointed , internodes hollow or solid; branches arising singly from nodes and subtended by a leaf sheath and 2-keeled prophyll, often fascicled in bamboos.
Leaf Arranged alternately in 2 ranks , differentiated into sheath, blade , and an adaxial erect appendage at sheath/blade junction (ligule) ; leaf sheath surrounding and supporting culm-internode, split to base or infrequently tubular with partially or completely fused margins , modified with reduced blade in bamboos (culm sheaths) ; leaf blades divergent, usually long, narrow and flat, but varying from inrolled and filiform to ovate , veins parallel, sometimes with cross-connecting veinlets (especially in bamboos) ; ligule membranous or a line of hairs.
Inflorescence An open, contracted , or spikelike panicle, or composed of lax to spikelike racemes arranged along an elongate central axis, or digitate, paired , or occasionally solitary; axillary inflorescences often many, subtended by spatheoles (specialized bladeless leaf sheaths) and gathered into a leafy compound panicle.
Flower Spikelets often aggregated into complex clusters in bamboos. Spikelets composed of distichous bracts arranged along a slender axis (rachilla) ; typically 2 lowest bracts (glumes ) empty, subtending 1 to many florets ; glumes often poorly differentiated from accompanying bracts in bamboos. Florets composed of 2 opposing bracts enclosing a single small flower, outer bract (lemma) clasping the more delicate, usually 2-keeled inner bract (palea) ; base of floret often with thickened prolongation articulated with rachilla (callus) ; lemma often with apical or dorsal bristle (awn ), glumes also sometimes awned . Flowers bisexual or unisexual ; lodicules (small scales representing perianth) 2, rarely 3 or absent, 3 to many in bamboos, hyaline or fleshy ; stamens 3 rarely 1, 2.
Fruit Normally a dry indehiscent caryopsis with thin pericarp firmly adherent to seed, pericarp rarely free, fleshy in some bamboos; embryo small or large; hilum punctate to linear.
Biology Multiplication by seeds and vegetative multiplication by long rhizomes. Seed is spread when adhered to clothing, fur, etc. or as a contaminant of hay and fodder. Seeds also float and can be spread by floodwaters. A prolific seeder, however seeds are reported to be relatively short lived, approximately three years. Seed is spread when adhered to clothing, fur, etc. or as a contaminant of hay and fodder. Seeds also float and can be spread by floodwaters. A prolific seeder, however seeds are reported to be relatively short lived, approximately three years.' (Smith, 2002; p. 56).
Ecology This species can grow in a wide range of soils. It is adapted to a wide range of soil and climatic conditions. It is particularly adapted to light textured soils but also grows well in heavy textured soils. It is commonly found in cultivated upland crops, roadsides, pastures, waste areas, around corrals, and along railroads and cattle trails. Both seeds and leaves contain phenolic acids that are allelopathic to other plants' (Holm et al., 1997; pp. 6-7). 'Found in a wide range of habitats. Common on roadsides, disturbed areas and around settlements. Known to invade pastures and out-compete more desirable native species. Also a weed of crops and a serious contaminant of wool' (Smith, 2002; p. 56).
World Distribution Northeast Tropical Africa: Sudan, East Tropical Africa: Tanzania; Uganda, West-Central Tropical Africa: Cameroon; Central African Republic; Zaire, West Tropical Africa: Burkina Faso; Cote D'Ivoire; Gambia; Ghana; Guinea; Guinea-Bissau; Liberia; Mali; Nigeria; Senegal; Sierra Leone; Togo.
Global Weediness Prohibited in Western Australia and a declared noxious weed in the Northern Territory.
Local weediness Benin: Rare and not abundant. Burkina Faso: Rare but abondant when present. Ghana: Frequent and usually abundant. Mali: Rare and not abundant. Senegal: Rare but abondant when present
Global control Good results have been gained where seeds have been vacuumed from the ground and then burnt (Smith, 2002; p. 56). Management options: http://www.afroweeds.org/network/pg/file/read/1902/general-guidelines-for-weed-management-in-lowland-rice
Uses Animal food, forage.
Reference Burkill, H. M. 1994. The useful plants of west tropical Africa. (Use Pl WT Afr) 2: 172. Hanelt, P., ed. 2001. Mansfeld's encyclopedia of agricultural and horticultural crops. Volumes 1-6. (Mansf Ency). Keay, R. W. J. and F. N. Hepper, F. N. 1953-1972. Flora of west tropical Africa, ed. 2. (F WT Afr). Turrill, W. B. et al., eds. 1952-. Flora of tropical East Africa. (F TE Afr). Zon, A. P. M. van der. 1992. Graminées du Cameroun. (Grass Camer).
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