Agave zebra, From northwestern Sonora, Mexico, is very similar in appearance to Agave americana. It's a bit smaller (3 to 4 feet), more heavily toothed and has faint horizontal bands of blue grey and grey green across the leaves, hence the name. It also bears an interesting pattern of the impression left by previous leaves as many agaves do.
     This one is unfortunately planted a little too close to the sidewalk, dumb move by me. I'll have to move it or take it out soon. But it's got about a half dozen pups that I've been watering as insurance in case it doesn't survive the move. Here's one that popped up next to a patch of Opuntia rufida several feet away from the momma. And the main plant with a rare dusting of desert snow.

One of the pups

A rare dusting of snow