Ageratum houstonianum

Miller

Gard. Dict. ed. 8, Ageratum no. 2. 1768.

Common names: Bluemink
Introduced
Synonyms: Ageratum conyzoides var. mexicanum (Sims) de Candolle
Treatment appears in FNA Volume 21. Treatment on page 483. Mentioned on page 482.

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 glanddotted. 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: Flowering Jun–Aug.
Habitat: Disturbed sites, mostly coastal
Elevation: 0–20 m

Distribution

V21-1213-distribution-map.gif

Introduced; Ala., Conn., Fla., Ga., Mass., N.C., S.C., Tex., Mexico, Central America, Pacific Islands (Hawaii)

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.

Selected References

None.

Lower Taxa

None.

"fine" is not a number.

... more about "Ageratum houstonianum"
not tailed +, truncate +, rounded +  and obtuse +
scarious +
usually ovate +  and lanceolate +
usually terete +  and clavate +
spiciform +, racemiform +, paniculiform +  and corymbiform +
indeterminate +  and determinate +
Guy L. Nesom +
Miller +
decurrent +
not enlarged +
dissected +, lobed +, toothed +  and entire +
deltate;ovate or elliptic +
papillate +  and rugose +
(4-)5-angled;10-ribbed +
less linear;clavate +
Bluemink +
strigoso-hispidulous +
prismatic +
fertile +  and bisexual +
Ala. +, Conn. +, Fla. +, Ga. +, Mass. +, N.C. +, S.C. +, Tex. +, Mexico +, Central America +  and Pacific Islands (Hawaii) +
0–20 m +
strigoso-hispid +, puberulent +, pilose +  and glabrous +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Disturbed sites, mostly coastal +
cymiform +  and corymbiform +
in usually determinate , rarely indeterminate , arrays +  and singly +
indeterminate +
each +  and sessile +
4 cm40 mm <br />0.04 m <br /> (?) +
campanulate +
0.3 cm3 mm <br />0.003 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
3 cm30 mm <br />0.03 m <br /> (8 cm80 mm <br />0.08 m <br />) +
2.5 cm25 mm <br />0.025 m <br /> (4 cm40 mm <br />0.04 m <br />) +
lanceolate +  and lance-linear +
2-carpellate +
persistent +
coroniform +
stipitate-glandular +, pilose +  and viscid-puberulent +
Flowering Jun–Aug. +
eciliate +, stipitate-glandular +  and sparsely densely pilose +
30 +  and 40 +
subequal +  and unequal +
Gard. Dict. ed. +
bearing subulate enations +, hairy +  and bristly +
distinct +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
exalbuminous +
Introduced +
erect +  and decumbent +
appendaged +  and truncate +
hirsutulous +
papillate +
Ageratum conyzoides var. mexicanum +
Ageratum houstonianum +
Ageratum +
species +
campanulate +
indurate-subulate +  and tapering +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
30 cm300 mm <br />0.3 m <br /> (80 cm800 mm <br />0.8 m <br />) +
vine +, shrub +  and subshrub +