Shrubs, 50-150 cm. Stems erect, puberulous. Leaves opposite proximally, alternate on distal 1/3-1/2 of stem; petioles narrowly winged, 3-5(-8) mm; blades ovate to deltate-ovate, mostly 1-2 × 0.5-1.5(-2) cm, bases truncate to cuneate or attenuate, margins entire or shallowly crenate, apices acute to blunt or obtuse, abaxial faces gland-dotted. Heads clustered. Peduncles 1-3 mm, puberulent. Involucres 3.5-4.5 mm. Phyllaries: apices acute, abaxial faces puberulent. Corollas pinkish white to pink, glabrous. Cypselae sparsely hispidulous.
Flowering (Jul-)Aug-Oct(-Nov). Limestone slopes, ledges, alluvium, in brushy vegetation; 1300-2200 m; Ariz., N.Mex., Tex.; Mexico.
Duration: Perennial
Nativity: Native
Lifeform: Subshrub
General: Perennial subshrubs, to 150 cm tall, erect, herbage puberulent.
Leaves: Leaves opposite proximally, alternate distally, thickish, broadly ovate, to 1.5 cm long, margins entire to crenate-serrate, obtuse at the tip, truncate, attenuate, or cuneate at the base, stipitate glandular below, petioles narrowly winged.
Flowers: Flowers pinkish-white to pink, in clustered heads of 10-30, lobes glabrous, involucres 3-5 mm high, the phyllaries with acute tips, the abaxial faces puberulent, borne on peduncles 1-3 mm; flowering September-October.
Fruits: Achenes sparsely hairy.
Ecology: Found on limestone substrates and alluvium on ledges and slopes, in brushy vegetation; 5,000-6,000 ft (1524-1829 m).
Distribution: se AZ, sw NM, sw TX; Mexico.
Notes: Ageratinas are fragrant composite herbs or shrubs, with sweet-smelling flowers, in our region they often grow in shady areas and are distinguished by having usually opposite, often triangular to ovate leaves, clusters of terminal heads with all white to cream disk flowers in which the stigmas stick out like threads, and a pappus of bristles. A. wrightii is the only species in the region with woody stems and branches, has short hairs on most parts and broadly ovate to rounded-triangular leaves with margins entire or shallowly toothed.
Ethnobotany: Unknown
Etymology: Ageratina is a dimunitive of Ageratum, which is from Greek ageratons for not growing old, while wrightii is named for Charles Wright (1811-1885), a naturalist who collected specimens for Harvard.
Synonyms: Eupatorium wrightii
Editor: LCrumbacher 2011, FSCoburn 2014
