Here are some pictures of the blue agaves along the Guy Fleming Trail in Torrey Pines State Reserve. A docent (my father) tells me they're "exotics" - not native but planted (originally from Mexico) - but since they were planted by naturalist Guy Fleming himself, they've been allowed to stay.
Good thing, too! Their bluish color is cooling and mysterious. The large lobes curl and fold elegantly. But the neatest thing are the spiny shadows on the lobes, which go in diagonals, sometimes intersecting. The serrated lines are imprinted as new lobes, curled tight in the center of the plant, push out against the others wrapped around them. Are they ornaments of family tradition or the scars of the struggle of generations?