My guess is that they are made of gumpaste and are no particular flower, just "flower-shaped." You can use a small blossom cutter for the smaller ones. The big ones look like each petal was cut and then assembled with stamens or something to represent stamens.
They are just made with a five petal blossom cutter , in different sizes. They could be made from either flowerpaste or fondant with tylose in it.
Very easy to make. The stamens are made from cotton by the looks of it. I use quilting cotton when I do this stiffened with just a little shortening to help them stand up.