There are a number of places we can see delicious mushrooms growing in-game, I too wish we could harvest them. (There are oyster mushrooms some places in Groddle Meadows, and I think straw mushrooms in callopee?)
Also, anyone *should* be able to harvest mushrooms but those who haven't learned enough levels of Mycology has a chance of being poisoned (losing mood/energy debuff)
It would also be great too have an area where the houses are mushrooms. Please not only smurf style houses, but also other kinds of mushrooms (e.g. Lycoperdon family, morels and jelly-like mushrooms) preferably in a gloomy atmosphere with spores flying around.
If you have no levels in the associated skill (Botany II? Mycology I?) you can only choose to Taste test before harvesting. This is similar to the massage/pet requirement for piggies and butterflies. Taste testing comes with a chance of either debuff or death. If the mushrooms are edible (no debuff or death on random roll) then you can harvest them 1x per day.
Examine is only available at higher levels of the associated skill. If you are more advanced in that skill, you could skip the Tastetest option and choose Examine instead, and harvest more per day or more times per day, as with trees.