The epidermis of grasses contains specialized cells which provide characters for the assignment of genera to subfamilies. The epidermis can be easily removed for preparation of slides by heating pieces of fresh or rewetted leaves in 40-80% solutions of HNO3, with addition of KCIO3, 1-2%, for very fibrous leaves. After its removal, the epidermis is washed in water, neutralized with KOH, stained in fast green or chlorazol black E, dehydrated, cleared, and mounted in Diaphane or balsam.