Explanation:
I assume the sequence inside the bunch of 4 picked flowers does not matter (a selection of e.g f1, f4, f5, f7 is the same as f4, f7, f1, f5).
and of course, repetitions don't make sense here (e.g. the same flower can't be picked twice).
then it is a combination of 4 items out of 8 :
8! / (4! × (8-4)!) = 8×7×6×5 / (4×3×2) = 7×2×5 = 70
there are 70 different ways to select 4 different flowers out of 8.