Anemones

I Had some green blobs attached to my filter which I took for jelly fish. When
I took them off the fiter and put them in a bowl, I could see they were not
jelly fish but small tiny anemones. I put them in my tank attached them to a
piece or small rock, and have watched them grow some are as big as nickels some
smaller still. They are getting stems and are now turning white, they are
clear, but I have never seen an anemone like them. They don't look like any
picture of any one I have ever seen. I had some bad brown ones I had to
eliminate from my tank that came off some live rock I bought after I found
these. Can only suppose I got them from the same source, a live rock. Any
one have any ideas on what kind they can be? They are growing stems now and
look clear to whithish. The stem on one is almost 1/2 inch already. MB