They are edible. Actually, all foraged 'mushrooms' are edible in game and tend to have a few bites each. Be careful, because some mushrooms (and other forageable items) are poisonous. I believe that trollfear may be among those that will adversely affect your health.

- Overlord EK

>You now regard Eorgina with a warm demeanor.

From my old UFS (which at this point is woefully out of date, with most info compiled over a decade ago), the following mushrooms are all types that can be foraged and are likewise edible:
Black hook, black trafel, flathead, genkew, red trafel, red vornalite, spotted heart, striped heart, white hook, and withered black

In addition, poisonous mushrooms that can be foraged (and eaten) are blue trafel, daggerstalk, soft white, and trollfear. The blue trafel and soft white mushrooms only poison at 5per/dissipating 1per per bite, while daggerstalk and trollfear poison at 10per/dissipating 1per per bite.

Mushrooms apparently all have 3 bites each, and can't be bundled. If you're looking for trollfear specifically, they are reeeeeally common and grow in many climate (confirmed: hot damp, humid, most, temperate) and most terrain (confirmed: coniferous forest, cultivated, deciduous forest, grassland, hilly, muddy wetlands) types.

Happy foraging!

- Overlord EK

>You now regard Eorgina with a warm demeanor.