Ageratina herbacea

(A. Gray) R. M. King & H. Robinson

Phytologia 19: 222. 1970

Common names: Fragrant snakeroot
Synonyms: Eupatorium herbaceum (A. Gray) Greene
Basionyms: Eupatorium ageratifolium var. herbaceum A. Gray
Treatment appears in FNA Volume 21. Treatment on page 551. Mentioned on page 548.
Click plate for higher resolution version.
Perennials or subshrubs, (20–)30–60(–80) cm (woody crowns and woody rhizomes). Stems erect (brittle), minutely puberulent. Leaves opposite; petioles 10–25 mm; blades triangular to lanceolate-ovate or ovate, 2–5(–7) × 1.5–3.5(–4.5) cm, bases truncate to shallowly cordate, margins dentate to serrate-dentate, abaxial faces sparsely hispidulous to glabrate, eglandular. Heads clustered. Peduncles 4–15 mm, puberulent. Involucres 4–5 mm. Phyllaries: apices acute, abaxial faces granular-puberulent. Corollas white, glabrous. Cypselae finely strigose-hispidulous. 2n = 34.

Phenology: Flowering (Jul–)Aug–Oct.
Habitat: Pine, pine-oak, juniper, and pinyon-juniper woodlands, rocks along streams, slopes, ridges, washes
Elevation: 1400–2700(–2900) m

Distribution

V21-1398-distribution-map.gif

Ariz., Calif., Colo., Nev., N.Mex., Tex., Utah, Mexico (Baja California, Chihuahua, Coahuila, Sonora).

Discussion

Ageratina herbacea is recognized by the distinctive color of its usually yellow-green, sometimes grayish, leaves, granular-puberulent involucres (with minute, thickened, eglandular hairs), and woody rhizomes.

References

None.

Lower Taxa

No lower taxa listed.