Plumbago scandens L.
A species with prominently stipitate-glandular calices found primarily south of the United States, entering the country peripherally in Arizona, Texas, and Florida.
Flowers in Barranca de Batopilas, east side of the Sierra Madre Occidentál, Chihuahua, Mexico, 22 Mar 2007.
Calices in Barranca de Batopilas, 22 Mar 2007.