In horticulture the definition and use of the terms cultigen and cultivar has varied. The words "cultigen" and "cultivar" may be confused with each other. Ube is believed to be a true cultigen, only known from its cultivated forms. The terms "cultigen" and "cultivar" may be confused with each other. Purple yam is believed to be a true cultigen, only known from its cultivated forms. Cultigen and cultivar may be confused with one another. The first record of a named cultigen occurs in "De Agri Cultura". The replacement of the expression "cultivated plant" with the word "cultigen" is not universally accepted. The Red Delicious is a clone of apple cultigen, now comprising more than 50 cultivars. It is a true cultigen and does not exist in its wild state. In Japan, the cultigen is called "shiso" (; ). He also coined the words "cultivar", "cultigen", and "indigen". A dainty slow-growing, early white-flowering cherry, it is a century-old cultigen from Hondo, Japan.