"O225-1" is a seedling that I"ve mentioned before (see blog post: Hulthemia Traits, the Good and the Bad). It is one of the showiest and most floriferous Hulthemias that I have raised from seed.
It turns out that this seedling is quite fertile: it sets hips easily and the seeds germinate very well. In the referenced blog post above, I mentioned that unfortunately this seedling has a tendency for "dieback", which is sometimes seen in Hulthemias. I am wondering if the same cause for dieback is what affects it's hips causing them to develop their unusual appearance as they mature.
It almost looks as if the skin of the hip is unable to grow as the hip swells, causing the skin to crack as it stretches. It is only a guess, but perhaps this same effect results in girdling of the canes which causes the dieback. Fortunately, I see dieback in only a few of it's offspring.