On the more hopeful side, another such amphidiploid (probable or genuine) could be produced by anyone who had the right “parts”.
While checking on possible progeny of Basye’s plant, I saw what appears to be something even more interesting: Kim Rupert’s self-seedling from Basye’s. White (mostly) and perpetual. That should give more immediate results … assuming it is still around.
And that reminded me of another Rugosa oddity mentioned by Graham Thomas (1994).
At some time before 1905, > R. roxburghii > was crossed with > R. rugosa > Thunb., ever a fertile parent, and the result partakes equally of both, being a good dense bush of some 2 m, well clad in its crisp foliage, amongst which the wide pale flowers tend to hide themselves. The stems are prickly like those of > R. rugosa > and the bark does not peel. It is interesting that the rounded, large heps are bristly and have some orange colouring. It was named > R. > x > micrugosa > Henkel.
During his experimental work with the parentage of roses at Cambridge in the second quarter of this century, Dr C.C. Hurst raised seedlings of this cross, one of which was named > R. > x > micrugosa > ‘Alba’. Apart from being of rather more upright habit, it is in other respects a replica of the original but of important garden value because the > white flowers are produced not only at midsummer, but onwards throughout the growing season> . They are, moreover, very fragrant. This might prove to to be a fertile parent and thus bring both species into today’s hybrids. They would be very hardy.
Then there is yet another, raised by Gustafsson (1944).
R. canina II x rugosa: 1934-4 — This series consists of two individuals. One is a monosomic plant showing almost no trace of the father but also being very unlike the mother. It is smaller and less vigorous than its sister-plant, having few and rather weak prickles, small purely white petals, a light-green colour on stem and leaves, and lacks anthocyanin. It is less winter-hardy than its sister-plant; during the cold winters 1941 and 1942 the superterrestrial parts were entirely killed. It cannot be a monosomic of the mother-plant since the meiotic behaviour is that typical of canina-rugosa hybrids. Therefore in this case the loss of one chromosome obliterates the characters brought in by the rugosa genome.
‘White Surprise’ [R. bracteata x R. rugosa rubra] is at least a little surprising.
‘Nyveldt’s White’ may be another instance, having been raised from three pinks. [R. rugosa rubra x Rosa cinnamomea] x Rosa nitida.