Ageratina altissima var. altissima

Common names: Common white snakeroot eupatoire rugueuse
Synonyms: Ageratina altissima var. angustata Fernald Eupatorium rugosum Reichard Eupatorium rugosum var. chlorolepis (B. L. Robinson) S. F. Blake Eupatorium rugosum var. tomentellum Eupatorium urticifolium
Treatment appears in FNA Volume 21. Treatment on page 549.

Phyllaries 3–5 mm, apices not cuspidate.

Phenology: Flowering Jul–Oct(–Nov).
Habitat: Moist forests, cove forests
Elevation: 10–800 m



N.B., N.S., Ont., Que., Sask., Ala., Ark., Conn., Del., Fla., Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Nebr., N.H., N.J., N.Y., N.C., N.Dak., Ohio, Okla., Pa., R.I., S.C., S.Dak., Tenn., Tex., Vt., W.Va., Wis.


Plants with narrow leaves, generally in the southwest part of the range of Ageratina altissima, have been recognized as var. angustata and were so mapped by A. F. Clewell and J. W. Wooten (1971), who indicated that all var. angustata occurs west of the Mississippi River and that this taxon was completely congruent in distribution with var. altissima. The present treatment confirms the westward tendency toward size reduction and observes that narrow-leaved plants occur widely through the southeast United States (including Arkansas, Kentucky, Louisiana, North Carolina, Oklahoma, Tennessee, and Texas). The transition is gradual and the region of intergradation is wide. In Texas, where the leaves mostly are narrow, plants with broad, cordate leaves are scattered through the range.

Selected References


Lower Taxa

Guy L. Nesom +
(Linnaeus) R. M. King & H. Robinson +
Ageratum altissimum +
Common white snakeroot +  and eupatoire rugueuse +
N.B. +, N.S. +, Ont. +, Que. +, Sask. +, Ala. +, Ark. +, Conn. +, Del. +, Fla. +, Ill. +, Ind. +, Iowa +, Kans. +, Ky. +, La. +, Maine +, Md. +, Mass. +, Mich. +, Minn. +, Miss. +, Mo. +, Nebr. +, N.H. +, N.J. +, N.Y. +, N.C. +, N.Dak. +, Ohio +, Okla. +, Pa. +, R.I. +, S.C. +, S.Dak. +, Tenn. +, Tex. +, Vt. +, W.Va. +  and Wis. +
10–800 m +
Moist forests, cove forests +
Flowering Jul–Oct(–Nov). +
Illustrated +  and Endemic +
Ageratina altissima var. angustata +, Eupatorium rugosum +, Eupatorium rugosum var. chlorolepis +, Eupatorium rugosum var. tomentellum +  and Eupatorium urticifolium +
Ageratina altissima var. altissima +
Ageratina altissima +
variety +