Eucalyptus spp. of the family Myrtaceae. Native to Australia. Also sometimes spelled morrell. Includes at least E. longicornis (generally called just morrel or red morrel), E. melanoxylon (generally called black morrel), and E. oleosa (generally called just morrel or red morrel), and I have no idea which of them are represented on this page.
web pics:
burl
pen blanks, not listed as burl but clearly they are
