Ageratum conyzoides L.
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Authority
Acevedo-Rodríguez, Pedro & collaborators. 1996. Flora of St. John, U.S. Virgin Islands. Mem. New York Bot. Gard. 78: 1-581.
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Family
Asteraceae
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Scientific Name
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Description
Species Description - Erect herb to 1 m tall, few-branched, pubescent; stems pilose. Leaf blades 2-8 x 1-5 cm, ovate, chartaceous, pilose, also glandular on lower surface, the apex mostly obtuse, the base acute to rounded, the margins crenate; petioles to 3 cm long, pilose. Inflorescence an irregularly branched panicle in the upper third of the plant, of several cymose clusters to 3x 4 cm with to about 25 heads. Heads ca. 40-70-flowered, to 5.5 mm tall and broad; involucre bell-shaped to hemispheric, to ca. 4 mm tall, 2-seriate; involucral bracts lanceolate, 2- or 3-striate, apically acuminate, sparsely pilose to glabrous; receptacle ca. 0.8 mm broad; peduncles 3-10 mm long, pilose, bracteolate. Corollas 1.5-2.0 mm long, glabrous or sparsely pilose, cream-colored to more commonly pale blue. Achenes 1.2-1.7 mm long, black, the angles with bristles; pappus awns 1.5-2.0 mm long, slightly longer than corollas, the pappus rarely reduced to a crown.
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Distribution
Occasional in open or disturbed areas. Along road to Bordeaux Mountain (A2858), Emmaus (A3149), Rosenberg (B291). Also on St. Croix, St. Thomas, and Tortola; native to the neotropics but adventive in the subtropics and in the paleotropics.
Tortola Virgin Islands South America| Saint Thomas Virgin Islands of the United States South America| Saint Croix Virgin Islands of the United States South America|