The parentage of seedling no. 4141 (confirmed in the 1955 reference to be 'Princeps') is given as a cross between 'Hadley' and R. gigantea in the 1938 and 1939 newspaper articles. This confirms the references, at the time of its introduction as 'Princeps', that it is a Hybrid Gigantea.

My observations from growing 'Princeps' is that apart from the large, elegant semi-double flower and climbing tendency there isn't much in its appearance of R.gigantea itself. Neither does the foliage shape show much Gigantea influence. However, in other respects this cross makes perfect sense. My 'Princeps' doesn't set hips, and this strongly suggests that it is a triploid which is what one would expect from crossing R. gigantea with a Hybrid Tea. Also, the velvety crimson colour and the beautiful, strong damask scent can be explained by 'Hadley' being one parent, and its spring-only flowering characteristic can be explained by having R. gigantea as the other parent.

It isn't very clear from the two newspaper references whether the cross is ('Hadley' x R. gigantea) or (R.gigantea x 'Hadley') but if I had to take an educated guess I would say 'Hadley' was the seed parent, simply because from a practical point of view it would have been easier to pollinate 'Hadley' with the pollen of Gigantea, rather than vice versa. Also the 1938 reference appears to have come from Clark himself, and the 1939 reference is a bit more vague.

I'd also add that Clark's description of it as 'straggling' is right on the mark for me although I don't give mine anything to climb on. It is a beautiful flower and perfume though and despite it only flowering once a year, I wouldn't want to be without it.

I was wondering if anyone might have access to the 1944 Australian Rose Annual to upload the black and white photo of 'Princeps' on page 23 (as described in the references here)? I'd be very interested in seeing it.