Tilia × europaea, generally known as the common lime (British Isles) or common linden (North America), is a naturally occurring hybrid between Tilia cordata (small-leaved lime) and Tilia platyphyllos (large-leaved lime). It occurs in the wild in Europe at scattered localities wherever the two parent species are both native. It is not closely related to the lime fruit tree, a species of citrus. (Wikipedia)