Summary ³

Ageratum conyzoides (Billygoat-weed, Chick weed, Goatweed, Whiteweed; Ageratum conycoides L., Ageratum obtusifolium Lam., Cacalia mentrasto Vell.) is native to Tropical America, especially Brazil. Herb 0.5–1 m. high, with ovate leaves 2–6 cm long, and flowers are white to mauve.

Description ⁴

Annuals, perennials, or sub-shrubs, 20–150 cm (fibrous-rooted). Stems erect, sparsely to densely villous. Leaf blades ovate to elliptic-oblong, 2–8 × 1–5 cm, margins toothed, abaxial faces sparsely pilose and gland-dotted. Peduncles minutely puberulent and sparsely to densely pilose, eglandular. Involucres 3–3.5 × 4–5 mm. Phyllaries oblong-lanceolate (0.8–1.2 mm wide), glabrous or sparsely pilose (margins often ciliate), eglandular, tips abruptly tapering, subulate, 0.5–1 mm. Corollas usually blue to lavender, sometimes white. Cypselae sparsely strigoso-hispidulous; pappi usually of scales 0.5–1.5(–3) mm, sometimes with tapering setae, rarely 0. 2n = 20, 40.

General habitat ⁵

"Most abundant weed of disturbed ground and fallows, damp places and forest undergrowth. Aggressive colonizer. Plains from the coast to 1300m. Native to America, now a common weed of all warm countries."

Global distribution ⁶

Tropical and subtropical regions of the world.

Flowring and fruiting ⁷

Oct-June

Sources and Credits

1. (c) Mark Hyde, Bart Wursten and Petra Ballings, some rights reserved (CC BY-NC), https://www.zimbabweflora.co.zw/speciesdata/images/15/158650-7.jpg
2. (c) Kai Yan, Joseph Wong, some rights reserved (CC BY-NC-SA), https://www.flickr.com/photos/33623636@N08/6248053101/
3. Adapted by Chandan Pandey from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Ageratum_conyzoides
4. (c) Missouri Botanical Garden, 4344 Shaw Boulevard, St. Louis, MO, 63110 USA, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/4989943
5. (c) India Biodiversity Portal, some rights reserved (CC BY), http://eol.org/data_objects/26331395
6. (c) Bibliotheca Alexandrina, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/16900612
7. (c) Chandan Pandey, some rights reserved (CC BY-SA)

More Info

• iNat taxon page
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