Flora of North America species comparison

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Ageratina havanensis

Ageratina altissima

Havana snakeroot, shrubby boneset, white mistflower, white shrub mistflower

white snakeroot
Habit Shrubs [trees], (30–)69–150(–200) cm. Perennials, (30–)50–80(–120) cm (bases usually fibrous-rooted crowns, sometimes rhizomatous).
Stems

erect (brittle), puberulent to glabrous.

ascending to erect, sometimes semiscandent, puberulent (hairs minute, crisped).
Leaves

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.

opposite;

petioles (5–)10–30(–50) mm;

blades usually deltate-ovate to ovate or broadly lanceolate, sometimes ovate-lanceolate, 4–11(–13) × 2.5–8(–9) cm, bases usually rounded to truncate or obtuse, sometimes cordate, margins coarsely and doubly incised-serrate, apices usually acuminate.
Peduncles

2–14 mm, minutely puberulent.

1–5 mm, puberulent.
Involucres

4–6 mm.

4–5 mm.
Corollas

white to slightly pinkish, glabrous.

white, lobes sparsely short-villous.
Phyllaries

apices acute, abaxial faces glabrous or nearly so.

apices acute, abaxial faces glabrous or sparsely and finely villous.
Heads

clustered.

clustered.
Cypselae

hispid.

glabrous.
2n

= 34.

Ageratina havanensis

Ageratina altissima
Phenology Flowering mainly (Sep–)Oct–Nov(–Dec), also Apr–Jul.
Habitat Bluffs, limestone outcrops and slopes, ledges along streams, often in oak-juniper woodlands
Elevation 100–900 m (300–3000 ft)
Distribution
from FNA
TX; Mexico; West Indies (Cuba)
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; CT; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; ND; NE; NH; NJ; NY; OH; OK; PA; RI; SC; SD; TN; TX; VA; VT; WI; WV; NB; NS; ON; QC; SK
[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.)

Varieties 2 (2 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Key
1. Phyllaries 3–5 mm, apices not cuspidate
var. altissima
1. Phyllaries 4–7 mm, apices cuspidate to acuminate
var. roanensis
Source FNA vol. 21, p. 552. FNA vol. 21, p. 549.
Parent taxa Asteraceae > tribe Eupatorieae > Ageratina Asteraceae > tribe Eupatorieae > Ageratina
Sibling taxa
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
A. adenophora, 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
Subordinate taxa
A. altissima var. altissima, A. altissima var. roanensis
Synonyms Eupatorium havanense Ageratum altissimum
Name authority (Kunth) R. M. King & H. Robinson: Phytologia 19: 222. (1970) (Linnaeus) R. M. King & H. Robinson: Phytologia 19: 212. (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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