A frenulum (or frenum) is a small fold of tissue that prevents an organ in the body from moving too far.
Cover crops usually are grown to prevent soil loss from wind and water erosion. Use fast-growing cover crops, such as winter wheat or annual rye, on fall-spaded gardens. A second, and probably more important reason home gardeners should use cover crops is to improve soil structure and increase organic matter.
Quick Answer. There are nine standard varieties of tuber crops including cassava, yam, potato, sweet potato and aroids, such as carrots and turnips. Some tuber crops, such as yams and potatoes, are umbrella categories that contain a number of sub-species within their families.