Posted by scvirginia (Charleston, SC - Zone 9a) on Jun 25, 2020 7:12 PM concerning plant:
Description from the 1933 catalog, Royal Iris Gardens (J. C. Nicholls, Jr., Camillus, NY), p.72:
ELEPHANTINA. 3 ft. Pure beautiful ivory white. Blooms of good size and a fine grower. Very floriferous and pretty.