Flora of North America species comparison

The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

Ageratina adenophora

Ageratina aromatica

Crofton weed, eupatory, Mexican devil, sticky snakeroot, thoroughwort

lesser snakeroot, small-leaf white snakeroot
Habit Subshrubs, 50–220 cm. Perennials, 30–80(–100) cm.
Stems

(usually purplish when young) erect, stipitate-glandular.

erect, villous-puberulent.
Leaves

opposite;

petioles 10–25 mm;

blades (abaxially purple) ovate-lanceolate or ovate-deltate to lanceolate-ovate, (1.5–)2.5–5.5(–8) × 1.5–4(–6) cm, bases cuneate to obtuse or nearly truncate, margins serrate, apices acute to acuminate, abaxial faces stipitate- to sessile-glandular.

opposite;

petioles 1–8(–12) mm;

blades narrowly to broadly deltate to nearly ovate or lanceolate, 2–7(–9) × 1.5–4 cm, (usually subcoriaceous) bases rounded or truncate to barely cuneate or subcordate, margins usually crenate, sometimes crenate-serrate to dentate or subentire, apices acute to obtuse, faces minutely pilose.
Peduncles

5–12 mm, densely stipitate-glandular and sometimes also sparsely viscid-puberulent.

2–9 mm, densely and closely puberulent.
Involucres

3.5–4 mm.

3.5–5 mm.
Corollas

white, pink-tinged, lobes sparsely hispidulous.

white, lobes sparsely villous.
Phyllaries

apices acute, abaxial faces stipitate-glandular.

apices acute, abaxial faces puberulent to villous-puberulent.
Heads

clustered.

clustered.
Cypselae

glabrous.

usually glabrous or sparsely puberulent (near apices), rarely hirtellous on angles.
2n

= 51.

= 34.

Ageratina adenophora

Ageratina aromatica
Phenology Flowering Mar–Aug(–Sep). Flowering late Aug–Oct(–Nov).
Habitat Stream margins, ditches, road embankments, hillsides Sandy soils, burned pinelands, turkey oak sand ridges, pine-oak and oak-hickory upland woods, old fields, roadsides, fencerows, moist sites
Elevation 400–900 m (1300–3000 ft) 100–900 m (300–3000 ft)
Distribution
from FNA
CA; Mexico; Intoduced [Also introduced in Europe, Pacific Islands (New Zealand)]
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; CT; DE; FL; KY; LA; MA; MD; MS; NC; NJ; NY; OH; PA; RI; SC; TN; VA; WV
[WildflowerSearch map]
[BONAP county map]
Discussion

Intergrades (probable hybrids) between Ageratina aromatica and A. altissima were identified by A. F. Clewell and J. W. Wooten (1971) over a broad area of their sympatry. They also found intergrades between A. aromatica and A. jucunda where their ranges meet.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 21, p. 553. FNA vol. 21, p. 550.
Parent taxa Asteraceae > tribe Eupatorieae > Ageratina Asteraceae > tribe Eupatorieae > Ageratina
Sibling taxa
A. altissima, A. aromatica, A. havanensis, A. herbacea, A. jucunda, A. lemmonii, A. luciae-brauniae, A. occidentalis, A. paupercula, A. rothrockii, A. shastensis, A. thyrsiflora, A. wrightii
A. adenophora, A. altissima, A. havanensis, A. herbacea, A. jucunda, A. lemmonii, A. luciae-brauniae, A. occidentalis, A. paupercula, A. rothrockii, A. shastensis, A. thyrsiflora, A. wrightii
Synonyms Eupatorium adenophorum Eupatorium aromaticum, Eupatorium latidens
Name authority (Sprengel) R. M. King & H. Robinson: Phytologia 19: 211. (1970) (Linnaeus) Spach: Hist. Nat. Vég. 10: 286. (1841)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



Type/paste one or more Latin names into the boxes above; matching taxa will show up below the box as you type. You can use the up/down arrow keys to move through the list.

(If the plant you're looking for doesn't show up in the auto-complete list, that means it either isn't described in Flora of North America yet, or it's listed under a synonym. And please note that Flora of North America is still missing several plant families, including Fabaceae, Apiaceae, Boraginaceae, and Polemoniaceae.)

Choose a data source: Flora of North America

The species comparison tool is brought to you by:
Northwest Wildflowers