Flora of North America species comparison

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Ageratina aromatica

Ageratina adenophora

lesser snakeroot, small-leaf white snakeroot

Crofton weed, eupatory, Mexican devil, sticky snakeroot, thoroughwort
Habit Perennials, 30–80(–100) cm. Subshrubs, 50–220 cm.
Stems

erect, villous-puberulent.

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

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.

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.
Peduncles

2–9 mm, densely and closely puberulent.

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

3.5–5 mm.

3.5–4 mm.
Corollas

white, lobes sparsely villous.

white, pink-tinged, lobes sparsely hispidulous.
Phyllaries

apices acute, abaxial faces puberulent to villous-puberulent.

apices acute, abaxial faces stipitate-glandular.
Heads

clustered.

clustered.
Cypselae

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

glabrous.
2n

= 34.

= 51.

Ageratina aromatica

Ageratina adenophora
Phenology Flowering late Aug–Oct(–Nov). Flowering Mar–Aug(–Sep).
Habitat Sandy soils, burned pinelands, turkey oak sand ridges, pine-oak and oak-hickory upland woods, old fields, roadsides, fencerows, moist sites Stream margins, ditches, road embankments, hillsides
Elevation 100–900 m (300–3000 ft) 400–900 m (1300–3000 ft)
Distribution
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]
from FNA
CA; Mexico; Intoduced [Also introduced in Europe, Pacific Islands (New Zealand)]
[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. 550. FNA vol. 21, p. 553.
Parent taxa Asteraceae > tribe Eupatorieae > Ageratina Asteraceae > tribe Eupatorieae > Ageratina
Sibling taxa
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
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
Synonyms Eupatorium aromaticum, Eupatorium latidens Eupatorium adenophorum
Name authority (Linnaeus) Spach: Hist. Nat. Vég. 10: 286. (1841) (Sprengel) R. M. King & H. Robinson: Phytologia 19: 211. (1970)
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).



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