I really think it is not a pressed glass. It does not have that lines that we find in the pressed glass.
I will try to describe it better, but i don't know the exact terms in english, so, please, correct me...
The poppies are on the underside, they are "carved" on the glass.
And the flowers are in a opaque white, the same color when acid is used on glass.
I took some other pictures using a black background, hope they are better. The pictures are from the backside.