My in-laws recently purchased a new home and along with it came quite an unusual specimen. This grafted tree is one-part oak and one-part pecan, joined just below the branches.

According to my friend Sarah Simmons, a Botanist at UT-Austin, grafting occurs when "a branch or bud of a desirable tree is taken and joined to the rootstock of another individual. Care is taken to assure that the cambium (or growing tissue) of the two are aligned so that actively dividing tissues come into contact and grow together. The cut tissues are protected until the graft takes."

"The process is more efficient than starting from seeds, it insures crop uniformity, and some crops are sterile (navel oranges) and must be artificially reproduced this way," Sarah says.

Perhaps the tree isn't as rare as I had thought, but it's still on my top-ten list of backyard anomalies. Bring on the wicked pecan/oak pie!