This is a October 7, 1999 flower from a 1999 seedling of Hamburger Phoenix X (Ivory Fashion X RSM K1).
Hamburger Phoenix is a cross of R. kordesii X seedling (Kordes, 1957).
Ivory Fashion is a cross of Sonata X Fashion (Boerner, 1958).
RSM K-1 is a cross of R. rugosa Alba X (J.W. Fargo X (Donald Prior X R. arkansana) X mixed R arkansana hybrids).
See Marshall, H.H., "RSM K1 and RSM K5 Rose Germplasm", HortScience, volumn 15, pages 205-206 (1980).
Marshall did a chromosome determination and confirmed that RSM K1 was a tetraploid.