Ageratina adenophora

(Sprengel) R. M. King & H. Robinson

Phytologia 19: 211. 1970

Common names: Crofton weed sticky snakeroot
Basionyms: Eupatorium adenophorum Sprengel Syst. Veg. 3: 420. 1826,; 4(qto.): 122, plate 346. 1820, not Michaux 1803
Treatment appears in FNA Volume 21. Treatment on page 553. Mentioned on page 547, 548.
Subshrubs, 50–220 cm. Stems (usually purplish when young) erect, stipitate-glandular. 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. Heads clustered. Peduncles 5–12 mm, densely stipitate-glandular and sometimes also sparsely viscid-puberulent. Involucres 3.5–4 mm. Phyllaries: apices acute, abaxial faces stipitate-glandular. Corollas white, pink-tinged, lobes sparsely hispidulous. Cypselae glabrous. 2n = 51.

Phenology: Flowering Mar–Aug(–Sep).
Habitat: Stream margins, ditches, road embankments, hillsides
Elevation: 400–900 m

Distribution

V21-1404-distribution-map.gif

Intoduced, Calif., Mexico, also introduced in Europe, Pacific Islands (New Zealand).

Discussion

References

None.

Lower Taxa

No lower taxa listed.