Cain's (1944) 13 criteria for centers of origin

1. Location of greatest number of species (taxa)
2. Location of greatest concentration of individuals (dominance)
3. Location of primitive and closely-related forms
4. Location of largest individuals
5. Location of greatest productivity and stability
6. Center of lines of migration radiating from a location
7. Location of greatest breadth of habitats (least dependence on rare habitat)
8. Center of lines of clinal variation radiating from location
9. Geographical affinity (all southern hemisphere)
10. Annual migration of birds (all species winter in Florida)
11. Seasonal appearance
12. Location of greatest number of dominant alleles
13. Greatest number of overlapping distributions