The spring and early summer blooming season is well underway in much of the country, and for many people that brings to mind some specific varieties of wildflowers or blooming trees or shrubs that they associate with a particular National Park Service area. Do you have any favorite "park flowers"?

Thoughts of spring wildflowers usually bring visions of lush hills and meadows with picturesque streams. But not the desert. Certainly not arid West Texas. Yet by April, especially in years following a wet autumn, wildflowers and cacti turn the rugged landscape of Big Bend National Park into a palette of rainbow hues. And migrating birds add their colorful magic to the trees and thorn-covered vegetation.

In its annual list of species considered to be candidates for Endangered Species Act protection, the U.S. Fish and Wildlife Service has cited at least 12 species that either can be found, or were found, in the National Park System.

With the Obama administration nearing the end of its first term, it has a track record for its stance on public lands in general and national parks specifically, and it's not as rosy as many conservationists had hoped for when the president came into office.