Hi Stall69, a flower frog sits in a vase or posy bowl and allows the flowers to be supported in the water, and was used prior to Oasis being invented....although some prefer to still use flower frogs. A posy trough is a long shallow trough shaped vase for holding flowers, and some that have a continuous aperture may hold a flower frog.
The link chezholloway gave was for a long flower frog that would have sat in the bottom of a long vase.
If you google flower frog and posy vase you will see what I mean. :sun:
Sorry Christine, we just clashed!! :kissy: