Bursera microphylla
Bursera microphylla is the most northerly member of the Burseraceae in North America and also perhaps the most xeromorphic (desert-adapted) species within the genus as it thrives in the extremely arid desert hills and mountains in northwest Sonora.[5][6][7] A few individuals can be found in the Fish Creek Badlands of Anza-Borrego Desert State Park, in a location between the Vallecito Mountains and Ocotillo Wells.Bursera microphylla reaches up to 10 m (33 ft)[10] in height and its bark is light gray to white, with younger branches having a reddish color.Gray Vireos and Ash- throated Flycatchers feed heavily on the ripe fruits of B. microphylla in the Puerto Lobos region of Sonora, Mexico during the winter months.[12] It has been suggested that the exfoliating papery bark of many of the trivalvate species may serve to attract the attention of birds and other animals from a distance as it rustles in the breeze (Rzedowski and Kruse 1979).