I did... I'm not questioning the parentage. I'm questioning the referece to Kordesii. 'Heidelberg' doesn't go back to Kordesii that I can see... the references don't say it does. I think there has been a typo made and the 'hybrid kordesii" was added by mistake. I'm thinking it should just read (Kordes, 1959).
You are correct. Modern Roses and some other publications classify 'Heidelberg' as a hybrid kordesii; however, we have a 1983 reference stating that this is an error. We have therefore changed the class designation in the name to "Floribunda clg."