Hello, I've had my white pine bonsai for almost a year now. Recently my moss has grown these flat sorta clover/lilly looking weeds. I have only tried to weed them and have been unsuccessful as they are firmly attached and take the moss right up with them. I just moved last week and it is a little hotter where I am now, so maybe my watering may be off. But is there anyone that can tell me what these are and maybe how to get rid of them? Thank you.

Here is a link to a picture:

http://picasaweb.google.com/lh/photo/jMeGbcbo5b7RmjwC2ySsOQ?feat=directlink