toadstools

I haven't tried straight down the middle... might have to experiment with that.

I've done like you said, cut off a small piece and always been successful. I've cut off the entire cap and been successful that way, too.
 
One of the main ideas behind successful propogation of leathers is to leave as small of an open wound as possible. Cutting down the middle will greatly increase your chance of failure. Who knows though... give it a shot if you want to. I personally wouldn't chance my 5" neon green toadstool by cutting it down the middle...
 
I have heard as far as cutting them in quarters and everything being fine, mines not big enough to frag yet so I have no first hand info for you.
 
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