This is perhaps the best known database to be found in the pattern recognition literature.
Fisher's paper is a classic in the field and is referenced frequently to this day.
(See Duda & Hart, for example.) The data set contains 3 classes of 50 instances each,
where each class refers to a type of iris plant. The Setosa class is linearly separable from
the other two classes. The last two classes are NOT linearly separable from each other.