Do you recognize this rose? Its pretty obvious, isn't it? 'Basye's Purple', right? Nope. This is one of four seedlings I grew several years ago from a cross of my "R. foliolosa" (in double quotes to indicate that I suspect this is not pure R. foliolosa, but a hybrid) and 'Little Chief', the Moore miniature descended from R. multibracteata and R. wichurana. (Code number 79-02-PFC)
I don't really understand how this happened, but it suggests that R. foliolosa is a bit of a trickster, capable of producing offspring that look similar to 'Basye's Purple' when crossed with a variety of other roses. It may be important to note that 'Little Chief' is almost certainly a diploid, and it is highly likely that this "R. foliolosa" is also. The thing to do now would be to grow a population of open pollinated seeds from the "R. foliolosa" I have and see what the offspring look like. I suspect there will be noticeable variation and a percentage will look like this. I have sent out some seeds from my "R. foliolosa" and so perhaps the recipients will be able to report their results.
PS: it is of interest to me that this purple seedling appears to be fertile as both seed and pollen parent and I will be working with it more, now that I know that. If anyone wants to try pollen from it, I am willing to share it. Comment to request it.