Ageratina rothrockii (A.Gray) King & H.Rob.

A white-flowered eupatorine, differing from A. herbacea in part in having corollas that are pubescent externally.

Pseudanthia at North Percha Creek, east side of the Black Range, Sierra County, New Mexico, 22 Aug 2009.

Achenes at North Percha Creek, 22 Aug 2009.

A cauline leaf at North Percha Creek, 22 Aug 2009.

Plant habit at North Percha Creek, 22 Aug 2009.

Pseudanthia on the Black Range crest trail, about half a mile south of Emory Pass, Grant County, New Mexico, 16 Sep 2011.