Natural Grafts at the Petrified Forest
This tree is a live oak growing from the soil overlying the petrified forest. It is of peculiar interest because its branches form two natural arches through having grown together, constituting natural grafts. We not infrequently see the trunks of trees thus united, but such union of branches is very unusual.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 11 Chapter 6