Thanks for clarifying that, Paul! I agree that R. bracteata is well and truly done as a possible parent in this case; I was mainly trying to reconcile your more recent comment with the one that was posted on the first page of the entry for 'Schneezwerg'.

I really don't feel that we have a good handle on the taxonomy and identification of the Central Asian species allied to R. laxa, especially in cultivation, and I have a strong suspicion that there may be more going on than simply different ploidy series within a single, highly variable species. At the very least, I would expect that we are dealing with taxonomically distinct subspecies, and probably more likely two or more "good" species between the diploids and tetraploids. If there are reported diploid forms of R. fedtschenkoana, I've never heard of them--I've only ever understood that species to be tetraploid, and most R. laxa chromosome counts I've seen tend to list that species as tetraploid as well. I'm very reluctant to consider 'Ross Rambler' to be just a selection of R. laxa until the variation within the species has been much better characterized, because it seems a lot like it could well belong to a separate species to me (I also agree that the extraordinary height reported for it at the time of selection was probably not significant in any way.) I'm sure you know that 'Ross Rambler' also flowers repeatedly (if sporadically) through the season.

Since 'Schneezwerg' is a diploid, it is almost impossible to believe that either of its parents could have been tetraploid; if that were the case, then it should almost certainly turned out to be triploid instead. That tends to rule out R. fedtschenkoana and most typical (tetraploid) forms of R. laxa as possible parents, I think. It's only so useful to guess what species material might have been available to its raiser, since there would have been a fair number of species introduced to European gardens and available at the time it was bred. Some of them may have been mislabeled, as has always been the case in horticulture, so even parentage reported in good faith sometimes has to be taken with a grain of salt.

The shape of the hips (and receptacles) does show evidence of some hybridization, of course, although I don't know that the specific shape is necessarily so inconsistent with R. beggeriana parentage. That isn't to say that R. beggeriana absolutely must have been the other parent, but the sometimes relatively high number of flowers per corymbose inflorescence also may point in that direction. I'm inclined to accept that as the likeliest species parent with R. rugosa, with possibly a diploid 'Ross Rambler'-like selection as another contender, but it would be very useful to see some genetic testing done with this variety and its assorted possible parent species.