Book  (2021)  Page(s) 203-204.  Includes photo(s).
 
Damask roses ...'Jonstorp' ...Known in culture in Sweden since the 1930s ....Description .... The DNA profile of 'Jonstorp' is closest to 'Celsiana' in the Damask group. Its similarity index is 70,8%. 'Frankfurt', a variety which is difficult to classify, has a similarity index of 56,5% with 'Jonstorp'. The next are the three Damask roses 'Erik', 'Järnvägeren' and 'Geschwinds Nordlandrose'...all with a similarity index of 53,8%.