When looking through the 115 "Magnolia" images at Acclaim Images.com this Magnolia Tree Blooming was a favorite.
All of their pictures are hand picked, availiable in a number of formats, and you can even get custom prints and posters.

Description:
Magnolia Tree Blooming
The shot was taken in the Dallas Arboretum garden during the spring. It was the beginning and except one flower, the tree was covered with buds.

Some related terms for more images:
magnolia stellata,  magnolia flowers,  white flowers,  white magnolias,