The mosses were a little crispy, seeing as how I visited during the dry hot part of the summer. I think that this temple would be even better to visit during the rainy season in the spring and earlier summer. I am not quite sure that I saw 120 species of mosses, but they covered all the available surfaces on the grounds.
One of my favorite parts were the grounds keepers who were sweeping the leaves off of the mosses and keeping them tidy. They were using traditional brooms, which I thought was a great touch. I would highly recommend it as a great place to see mosses, if you are ever in Japan. However it is not the place to go collecting. I had the urge to put some of the moss in my pocket, but I thought that would be frowned upon. So I resisted and instead took many photos to remember the visit.