- Callus is connective tissue initially
formed around a fracture (see fractures
and dislocations), and slowly ossified as repair proceeds. See also bone.
- In botany, callus is a protective mass of undifferentiated cells formed at the
site of a wound in a woody plant. Callus tissue is also formed at the
base of cuttings as they start to take root. Callus tissue is important
as the starting point for tissue culture of plants.