Mutation in axillary buds of trees overcoming self-incompatability? I seem to recall from either reading or lecture that there have been instances of trees that are self-incompatible accumulating enough mutations in an axillary bud that the resulting branch was able to pollinate flowers on other parts of the tree. Unfortunately, I do not have a source for this information. Are there recorded instances of this happening, or is this a figment of my fevered brain?

Recently, samples from different parts of cottonwood trees have been sequenced (Nature News). The conclusion:

> “The variation within a tree is as great as the variation across unrelated trees,” says Ken Paige, an evolutionary biologist at the University of Illinois at Urbana-Champaign, who led the team that made the discovery.

This doesn't say anything about overcoming self-incompatibility, and it probably depends on the mechanism of self-incompatibility if it can be overcome by accumulating mutations.