I want to learn to discern the various California species, but Pete Veilleux over at East Bay Wilds, who really knows his local native stuff, says it's a difficult task.
Among my classes this term are a couple or three that focus on local natural history. That should help.
Martin pointed out this gorgeous circle of manzanita leaves from Rob Herr, at Flickr. (He granted me permission to use the photo, it's not in the creative commons realm.)
The leaves are so beautiful and special. They're sclerophyllic, tough and a little leathery, to survive the hot, dry summers of their western habitats. The leaves chemically change soil to make it harder for competing plants to grow. And the colors, oh: they start so delicately green, and toughen to a darker green, turn reddish, then before they're gone, it's as if they self-immolate, without flames, they just dry and blacken. (They sometimes fall off before this stage, too, but it's weird, like someone's lit them.)
Their angle on the plant maximizes sun exposure when the sun is less direct and drying, in the morning and late afternoon, but minimizes it at midday, conserving moisture.
I love manzanita. Later, I'll write about the fire ecology around it and chaparral, and its magical bark, and what I want to do with the wood.