Black Tartarian Black Tartarian Black Tartarian (originally "Ronald's Large Black Heart") is an heirloom cultivar of cherry. It was brought from Circassia to England in the 1700s by a man named Hugh Ronalds, and from England it was brought to the United States in the 1800s. The fruit of the Black Tartarian is about one inch in diameter, with a unique taste and texture, but too soft for commercial shipping. It is primarily grown as a pollinator for other cherry varieties. The Black Tartarian cultivar is best suited for USDA Zones 5-7. It is a very vigorous, heavy-bearing variety, but is primarily
History of manifolds and varieties History of manifolds and varieties The study of manifolds combines many important areas of mathematics: it generalizes concepts such as curves and surfaces as well as ideas from linear algebra and topology. Certain special classes of manifolds also have additional algebraic structure; they may behave like groups, for instance. In that case, they are called Lie Groups. Alternatively, they may be described by polynomial equations, in which case they are called algebraic varieties, and if they additionally carry a group structure, they are called algebraic groups. The term "manifold" comes from German "Mannigfaltigkeit," by Riemann. In English, "manifold" refers to