Staghorn blossom

Photo by Marty Horowitz 4/17/2012

Staghorn Chollas (Cylindropuntia versicolor) are blooming. The species designation 'versicolor' refers to the fact that the flower color can vary: yellow, red, orange, pink, copper, green. You get the idea.
If you are interested in  looking up what scientific names mean, try the Botanary (botanical dictionary). Type the name in the search box in the upper right.
And if you are interested in the mathematics of plant growth, Smith College has great resources.