Very “fuzzy” on both sides of the leaves.

From what I understand, Rubus taxonomy is complicated, so if you ID this observation to species/complex/hybrid, please explain what field marks distinguish it as such. I am perfectly content to leave this observation at genus level.

I know the trailing vines and three-leaf clusters are often used as guidelines to ID R. ursinus. However, other Rubus species can also grow in such a way, especially as younger plants.