Burrs:

This is of the inside of the bowl blipped a couple of weeks ago. I have made a few attempts in recent days to capture in the hope of a sharper image. And have now decided to go with the above.

Taken from the internet:
Burrs (or burls) are the odd looking lumps seen on trees and are a result of abnormal growth within the tree. The grain pattern within these burrs is often full of whorls and swirls and the outer surface can have interesting peaks and shapes. It is the combination of unusual grain patterns, colouring and external shape that makes burrs so highly sought after when woodturning, for something out of the ordinary in turned wooden burr bowls.
The irregular grain and shape makes the woodturners task a little more difficult but the results make the extra effort worthwhile. Natural edge turned burr bowls either have the bark on or off and each creates a different overall effect for the bowl. Finishes are either oil or wax.