Marimo! Where? How?

Hi all! I love those Marimo!! But I can not make a trip to Hokkaido to get them. I'll be in Tokyo and I can't take any far away trips due to financial constraints. Is there anywhere in or around Tokyo that sells Marimo cell charms or keychains or what not? And could I take them back to the United States or would they be seized for being a plant? Do I state them on customs form too? Thank you!

Marimo can also be found in the Fuji Five Lake area, which is relatively close to Tokyo, but I am not sure how easy it is to find them in the local souvenir shops:
http://www.japan-guide.com/e/e6900.html

The easiest is probably purchase over the internet:
http://www.google.com/search?hl=&q=shop+marimo

They end up being made in China either way.

Yup, Uji is right as always except for one point (no big deal!!):

most of the Marimos sold on the net (but also the ones from Hokkaido) are ''made in USSR'' as it was called.

The ''real, original'' ones are more than hard to get because they are protected.

Thanks on the replies so far! 5 lakes is a bit far away too. Not as far as Hokkaido.. Oh well! Yes I've read that the marimo that are sold are not the ones in the lake that are protected, but they are part of the family? I guess the 'marimo' sold in pet stores here are usually pingpong balls covered in algae ;p