'Contrary to general opinion, the dogwood 'blossom' is not the true flower, but modified leaves known as bracts. In the center of the 'blossom' is the compact group of many flowers that turn to red berries in the late fall. In sunlight the glossy green leaves have a specular value that competes visually with the white bracts.' (Ansel Adams, Examples: The Making of 40 Photographs)
The image shows the general influence of Paul Strand, whose work Adams had seen in New York in 1936. Strand's meticulous use of toners - to make his whites shine against rich blacks had its effect on Adams, who thereafter carefully toned his work to enhance luminosity and the textural subtlety. Adams' other exquisite studies of the minutiae of trailside flora in the collection (see lots 1023 and 1025), are also strongly reminiscent of the older photographer.
Stillman, ed., Yosemite: Ansel Adams, Little Brown and Company, p. 41