Mushrooms are delicious and learning to identify them is interesting.
However:
In most survival situation food is not a high priority - most of us have more than enough 'stored resources' to last a week or so.
If you get lost in the woods overnight then eating random mushrooms is unlikely to be a life enhancing strategy.
The stories archive here is full of cases of people getting stung/bitten/injured trying to catch and eat something after they have been lost for a couple of hours.

I think our esteemed host mentions this in excusing why he felt obliged to include a fishing kit in the PSK.