Matsutakes may be the most popular mushroom I sell. They are very popular in Japan, and have been known to go for over 100 dollars a pound during peak season. Matsutakes will only grow in unique environments and cannot be cultivated. It is important to note that there are many different grades of matsutakes. The range usually starts at 1 (a fully closed cap mushroom) all the way to 5 (mushroom cap is completely open). These mushrooms are harvested between September and November. WIKIPEDIA has a lot of fun information about this mushroom.