Compilation
Ageratum houstonianum

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Name

Identification
Ageratum houstonianum Mill. [family ASTERACEAE ] (stored under name);
Related name
  • Ageratum mexicanum
  • Ageratum houstonianum
  • Ageratum conyzoides
  • Caelestina ageratoides
Common name
  • Bluemink, Flora of North America Vol. 21

Flora

Entry for Ageratum houstonianum Miller [family COMPOSITAE]
Herbarium
Flora of North America (FNA)
Collection
Flora of North America
Resource Type
Reference Sources
Entry From
Flora of North America, Vol 21,
Names
Ageratum houstonianum Miller [family COMPOSITAE], Gard. Dict. ed., 8, Ageratum no. 2. 1768
Ageratum conyzoides Linnaeus var. mexicanum (Sims) de Candolle [family COMPOSITAE]
Treatment Author(s)
Guy L. Nesom
Information
Annuals, 30–80 cm (fibrous-rooted). Stems erect to decumbent, sparsely to densely pilose. Leaf blades deltate to ovate, mostly 3–8 × 2.5–4 cm, margins toothed, abaxial faces sparsely to densely pilose, not evidently gland-dotted. Peduncles viscid-puberulent, pilose, and stipitate-glandular. Involucres ca. 4 × 5–6 mm. Phyllaries narrowly lanceolate (0.6–1 mm wide), stipitate-glandular, sparsely to densely pilose, eciliate or inconspicuously ciliate, tips gradually tapering, indurate-subulate, 0.8–2 mm. Corollas usually lavender, rarely white. Cypselae sparsely strigoso-hispidulous; pappi of 5 distinct, oblong scales 2–3 mm. 2n = 20.
Phenology
jun-aug (summer)
Altitude range
0–20 m;
Distribution
MexicoCentral AmericaintroducedPacific Islands (Hawaii).USA Ala.USA Conn.USA Fla.USA Ga.USA Mass.USA N.C.USA S.C.USA Tex.
Discussion
Ageratum houstonianum is apparently native to southeastern Mexico and Central America; the North American plants are escapes and naturalized from cultivars. M. F. Johnson (1971) observed that forma isochroum (B. L. Robinson) M. F. Johnson (type from the state of Veracruz, Mexico) sometimes may be nearly eglandular.
Native/Introduced
introduced;

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