This striking red and yellow flower is Western Columbine (Aquilegia formosa), a member of the Buttercup Family (Ranunculaceae). It's also known as crimson columbine and Sitka columbine. Aquilegia is Latin for eagle and probably refers to the talon-like nectar sacs. Formosa means beautiful.
Western columbine is extremely attractive to hummingbirds and bees. The flower is basically upside down, and each of the five tubular petals end in swollen nectar sacs. The five red sepals flare out like wings. The yellow stamens protrude out of the flower. After pollination, the flowers turn up towards the sky.
The leaves are deeply pinnately-lobed.
Desert princesplume (Stanleya pinnata) is one of my favorite desert wildflowers, with the distinctive yellow spikes of flowers seeming so out of place in a location where colors and shapes are often muted. 
It's a member of the Mustard Family (Brassicaceae), with flower parts in fours.
One of the neat things about desert princesplume is that there can be buds at the top, flowers in the middle, and seeds at the bottom of the stalk. They can grow to over five feet tall!
A deep purple flower decorating the foothills over the past couple of weeks is cleftleaf wildheliotrope (Phacelia crenulata). It has some better common names: notch-leaved phacelia, desert phacelia, scalloped phacelia, and heliotrope phacelia. It's a member of the Waterleaf Family (Hydrophyllaceae).
Flowers have five lobes, stamens that extend from the flower and are tipped in yellow, and often are in hairy, terminal coils that give it yet another common name: scorpionweed.
Addendum: I spotted a few of these all-white phacelia mixed in with the purple ones. Not sure what's going on here, but they were very pretty!
This dazzling bright yellow flower decorated a patch of ground in some sagebrush hills. It's called nakedstem sunray or naked stemmed daisy (Enceliopsis nudicaulis). It's obviously a member of the sunflower family. 
It is about a foot tall, the flower rising from a basal rosette of greenish-gray leaves. There are no leaves on the stalk, and just one flower head per stalk (peduncle). This is a flower that I'd like to add to my native flower garden, it's really eye-catching.
This beautiful blue showy family is a larkspur in the Buttercup Family (Ranunculaceae). It's Anderson's Larkspur (Delphinium andersonii). Larkspurs fall under the genus Delphinium, which is Latin for dolphin, referring to the resemblance of the flower buds to the swimming mammal. 
This particular flower is more purple than blue. The flowers are about 1 inch long. The spurs coming off the back of the flower are one of the distinguishing characteristics between species.
This pretty white flower is actually a noxious weed, Broadleaved Pepperweed (Lepidium latifolium), a member of the Mustard family (Brassicaceae). It's commonly called Tall Whitetop and also broadleaved peppergrass or perennial pepperweed.
It grows two to three feet tall on average and usually prefers wet areas, but can grow about anywhere. Once it becomes established, it takes over an area, outcompeting the native plants. It has robust, spreading roots, and digging or mowing encourages growth from the severed roots. It also produces a prodigious number of seeds, further spreading its extent. 
