ALLERGY AND ASTHMA IN THE SOUTHWESTERN UNITED STATES 

Desert Ragweed - Ambrosia dumosa
desert ragweed image
Photo courtesy of The Vascular Plant Herbarium, Arizona State University

Flowering Period in Southern Arizona:  May- November.  White bursage. Throughout Sonoran Desert. 
Shrub 2 ft high, leaves 3/4 in long                                   Back