Oyster Mushrooms are unique in the fact that the base of the mushroom, stem butts, can be used to propagate the mushroom. I bought an 80 cent mushroom from the store. I picked one that had a base that was not dried out and there were small pockets of fuzzy mycellium. I cut off the caps and upper half of the stems and fried them up, delicious. I pasteurized straw in water as I showed in my other mushroom post. Once cooled I placed the stem butt on top of the straw, closed the lid and waited. After a while the stem butt reverts back to a mycelium state and starts colonizing the straw. Another few weeks and the straw will be fully colonized ready to fruit or divided out to new growing mediums.