Flora of North America species comparison

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Ageratina adenophora

Ageratina havanensis

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

Havana snakeroot, shrubby boneset, white mistflower, white shrub mistflower
Habit Subshrubs, 50–220 cm. Shrubs [trees], (30–)69–150(–200) cm.
Stems

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

erect (brittle), puberulent to glabrous.
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.

persistent, opposite;

petioles 3–10(–15) mm;

blades deltate to broadly ovate or somewhat hastate, (2–)3–5(–8) × 2–5 cm, bases truncate to cuneate, margins dentate, apices acute, faces glabrous or nearly so, eglandular.
Peduncles

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

2–14 mm, minutely puberulent.
Involucres

3.5–4 mm.

4–6 mm.
Corollas

white, pink-tinged, lobes sparsely hispidulous.

white to slightly pinkish, glabrous.
Phyllaries

apices acute, abaxial faces stipitate-glandular.

apices acute, abaxial faces glabrous or nearly so.
Heads

clustered.

clustered.
Cypselae

glabrous.

hispid.
2n

= 51.

= 34.

Ageratina adenophora

Ageratina havanensis
Phenology Flowering Mar–Aug(–Sep). Flowering mainly (Sep–)Oct–Nov(–Dec), also Apr–Jul.
Habitat Stream margins, ditches, road embankments, hillsides Bluffs, limestone outcrops and slopes, ledges along streams, often in oak-juniper woodlands
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
TX; Mexico; West Indies (Cuba)
[WildflowerSearch map]
[BONAP county map]
Discussion

Ageratina havanensis apparently is the only species of the genus in the flora area with evergreen-persistent leaves.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 21, p. 553. FNA vol. 21, p. 552.
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. aromatica, 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 havanense
Name authority (Sprengel) R. M. King & H. Robinson: Phytologia 19: 211. (1970) (Kunth) R. M. King & H. Robinson: Phytologia 19: 222. (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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