Annual herbs (in ours). Lower leaves opposite, the upper
alternate. Leaves petiolate, ovate, crenate-serrate. Capitula
several-flowered in a dense corymb or occasionally a lax panicle,
homogamous, discoid. Involucre campanulate. Phyllaries 2-3-seriate, subequal, with membranous margins. Receptacular scales 0. Flowers blue, purple (rarely pink) or white. Anthers with an oblong apical appendage. Pappus usually of 5 fimbriate or lacerate scales, extended into scabrid awns. Derivation of name: Ageratum: Greek for not growing old, first applied to an everlasting. Worldwide: 44 species in tropical America. Zimbabwe: 1 cultivated taxon. |
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