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