Angiosperms, also known as flowering plants, are a diverse group of plants that produce flowers and bear their seeds in fruits. They are the largest and most diverse group within the kingdom Plantae, with about 300,000 species. Angiosperms represent approximately 80 percent of all known living green plants. They are vascular plants, meaning they have stems, roots, and leaves, and their ovules are fertilized and develop into a seed in an enclosed hollow ovary. Unlike gymnosperms, such as conifers and cycads, angiosperms seeds are found in a flower. Angiosperms have evolved specialized cells and tissues that carry out functions necessary to support, nourish, and extend the plant body, and have further evolved specialized vascular tissues (xylem and phloem) that translocate the water and nutrients to all areas of the plant body. Angiosperms are of special interest to humans because they provide many essential and useful products, from food to medicines, herbs, spices, oils, fats, natural rubber, wood, clothing fibers, and other products.