Persian Buttercups

This is the odd one out in the Ranunculus family. If the bulbs you planted were definitely labelled Ranunculus, then you have Ranunculus gramineus, so named because the leaves resemble grass.
A clump forming perennial, it grows to 18 ins. high, and bears yellow, cup shaped flowers in spring and early summer in Europe.

I found out this was a acidentheria! They are beautiful white delicate flowers with purple centers and a touch of yellow.