This rare hybrid has been reported in the literature a few times but has never been given a formal name. To see for myself what it looks like, a couple years ago I manually deposited pollen from Geum canadense onto several flowers of Geum aleppicum at a site where both occur. I marked the flowers that had been pollinated and returned later in the season to collect seeds.
I was able to grow out about 30 plants from the seeds and at the end of June of this year they finally bloomed. While the majority of plants appear to be straight G. aleppicum, one plant is an obvious hybrid. Success!
Overall the plants are most similar to G. aleppicum but with paler flowers that begin flowering around the same time as G. canadense (G. aleppicum starts flowering slightly earlier). Also notice that the petals are a bit more slender than is typical of G. aleppicum.
The following image shows the fertile fruit of G. aleppicum (left) and the sterile fruit of G. aleppicum × canadense (right). Geum hybrids are typically sterile, one exception being the hybrid of G. rivale and G. urbanum (G. × intermedium).
The foliage of the hybrid is similar to Geum aleppicum but the upper leaves are less divided. They are also not as dark green. It remains to be seen if they will darken when dried, a characteristic typical of G. aleppicum.
This last image shows the flower of the hybrid (middle) with flowers of the two parents, G. aleppicum (left) and G. canadense (right).