Hi, I am just a person from the internet who has fallen down a rabbit hole, and I hope you can help me. There are a few photos around the internet of roses with a double center - it is one flower from one stem, but there will be two “spirals” of petals in the center. I understand that “double” in the rose world refers the the number of petals, but I am trying to find out if there is a word for when there are two centers. I’ve searched for “conjoined” and “siamese”, but I don’t find much. I want to know why this happens and if it’s a trait that can be selected to result in a variety that produces these flowers always (or at least more often that not). Or is it a case-by-case mutation that is primerily dependent upon the environment? The closest thing to an answer I have found was when someone asked, and the response was a snarky explanation of “double”. Please excuse me if I misused any terminology or if it’s a dumb question overall, but I would really love to know.
I believe you are referring to “split centers”, when instead of the expected, single pointed center, the bloom shows two. Traditionally, that has been viewed as a fault, particularly in rose exhibiting. There have been a number of varieties infamous for the fault, Kordes Perfecta being one. There may be a genetic proclivity for it. If you study rose flower forms, you will see it’s pretty much half of the old fashioned “quartered bloom” form. Many Old Garden Roses have quartered form. Quite a few moderns, particularly the David Austin, Meilland Romantica and other European breeders’ offerings exhibit quartered forms.
Yes, split centers. Sometimes bull nose.
There are many types of doubling, and it is sometimes genetic inclination. Synstylae types can be known to have different genetics for doubling also, so it is not very clear cut. There is a paper out there about this, but I cannot recall where I read it about 5 years ago, or even if it was behind a pay wall.