In the May 2007 issue of WOOD magazine, issue 176, we featured an article titled The Many Faces of Maple.
"Ambrosia" is a term that's commonly applied to lumber from eastern red and silver maples that has streaks of color caused by an infestation of the ambrosia beetle.
Angel Stairs or Angel Step is a figure pattern found in lumber cut from trees that have twisted trunks, and is common in maples and walnuts.
Spalting is a figure pattern caused by fungus growing in trees and logs.
Bird's-eye is the name for a figure pattern most often associated with hard maple (acer saccharum), but I have found it in many other species, including koa, black walnut, cherry, Tasmanian blackwood, and a few rosewoods.
Crotch is a figure that develops when a tree knits a trunk to a branch or when two branches come together. The figure is also referred to as plume or a feather.