Like the King Trumpet, there is no base. The bottom parts of Maitake mushrooms are edible, but if you don’t want to eat the base, you can cut them off.
Maitake mushrooms have Proteolytic enzymes that prevent protein, such as eggs and meat, from solidifying. If you want your dish to solidify when cooking with Maitake, you should boil the mushroom for at least 30 seconds before adding it to your dish. On the other hand, one advantage of adding Mitake directly into your dish, is that it can help tough meat become tender.
Under the caps of Maitake is a part called the gill. The gills of the mushroom produce spores as it readies its self for reproduction. As the the mushroom grows the spores become more visible. These spores may be more visible but they do not effect the mushroom and are edible.
This is a ring mark from the cultivation base and is edible. If you do not like the look or texture you can cut the ring off.
Maitake mushrooms have a natural black pigment to them, thus making the liquid they produce black as well. It is not scum; it contains nutritious ingredients beneficial to health, like polyphenol. To get the most nutrition out of the mushroom, do not discard the liquid. One helpful suggestion is to use Maitake mushrooms in soups for creating a highly nutritious broth.