Melampodium sericeum
A low-growing, yellow-rayed Melampodium, similar to M. strigosum and M. longicorne; in fact, I am not totally certain which of the three is photographed. M. sericeum is found in northern Mexico but apparently does not enter the United States.
Flowering stems, south of La Concha Microundas along Chihuahua Hwy. 11, Chihuahua, Mexico, 9 Sep 2009. Photographed on a trip with the American Penstemon Society.
Pseudanthia, south of La Concha Microundas along Chihuahua Hwy. 11, 9 Sep 2009.
Closer view of a pseudanthium, south of La Concha Microundas along Chihuahua Hwy. 11, 9 Sep 2009. Note the inner phyllaries enfolding the ray florets.
Achenes of the ray florets, with the enfolding phyllaries removed, south of La Concha Microundas along Chihuahua Hwy. 11, 9 Sep 2009