Can You Solve This Rubus?

How many?

Here is a blackberry blossom that I spotted in the hedgerow between two fields.

By far the majority of such blooms have 5 petals. Even the adjacent buds have 5 sepals and so will have the usual 5 petals.

However, this one is a super flower and as such it deserves to be immortalised on Blip.

Rubus sp.