They are a “jelly fungus” with no gills and thick skin. Their underside is greyish.
When dried, their top will be solid dark-brown or black. Most dried ones still come from China.
They are pretty bland tasting. They are used more for “chew texture.”
Dried ones need to soak for at least half an hour. When rehydrated, they will swell to 2 to 5 times their dried size, and become a very dark-brown, almost black. Cut off the woody fibre near base and rub the mushroom with your fingers to free the grit, then rinse well.
After rehydrating, add to cooked dishes at the end so that they will stay chewy when cooked. Otherwise they won’t. Use up right away after rehydrating, as they won’t keep.
Often shredded for use in soups and in pork dishes.
Ultimately, it doesn’t really matter if you use Wood Ear Mushrooms or Cloud Ear Mushrooms; they are pretty interchangeable.
The Chinese were cooking with Wood Ear Mushrooms as early as 300 to 200 BC.
The various names for Wood Ear Mushrooms come from their looking like big ears growing out of the sides of trees.
The Chinese name “mu er” means wood ear; the Hawaiian name “pepiao” means ear.