Wood Ear showing in picture is the ready-to-cook look. It’s one kind of dry ingredient, you have to soak it in water for at least an hour before you cook it.
Wood ear has different names in English. This name should be translated directly from its Chinese name. A lot of times, it’s called ‘black fungus’.
Below are the links from wiki:
http://en.wikipedia.org/wiki/Auricularia_auricula-judae
http://en.wikipedia.org/wiki/Cloud_ear_fungus
http://en.wikipedia.org/wiki/Wood_ear
Some dishes cooked with black fungus:
Stir Fried Napa with Shrimp and Black Fungus