kenzan

An essential tool for ikebana (Japanese flower arranging).

They come in many different shapes and sizes, from only as large as the end of one's thumb to large enough to hold a pine bough.

A kenzan consists of a flat metal base with a large number of thick pins that will hold the stem of a flower or branch at the precise angle intended.

I have heard that these are sometimes called "frogs" in the West for some mysterious Occidental reason.

The reason may be this:
There are many pins/ribbons/medals worn by military members that have the detachable clamps on the backs. You push the pin through, then attach the backing, almost like an earring backing. Those little backing things are called "frogs," possibly for their squat, round shape. The kenzan are somewhat similar(in function, if not in appearance) possibly leading to calling them the same thing.

It is just conjecture, but if anyone has a better idea...