Called by many names - pin frog, kenzan, flower spikes, flower arranging frog, needle holder - these bases are particularly used in ikebana.I bought an assload at a recent estate sale and here's a stack of them set against the background of my green dining room. 
These pressed glass discs with holes are called "frogs" and are used for floral arranging. The frog is placed inside a vase and floral stems go in the holes. You can find them at flea markets, eBay and sometimes at garage sales.Here is how I display my collection.
