The World Checklist of Selected Plant Families uses the WGSRPD numeric codes for Levels 2 and 3. Hence to this degree of detail it gives the distribution of Magnolia grandiflora as "77 78 (79) (81) (85)".[29] The Level 2 codes 77 and 78 are South-Central U.S.A. and Southeastern U.S.A respectively; the absence of parentheses shows that the species is native to these regions. Parentheses around codes are used in the WCSP to show that the species is naturalized rather than native.