This is one of the best known
to be found in the machine learning literature.
It was introduced by the statistician Ronald Fisher in his 1936 paper “The use of multiple measurements in taxonomic problems”, Annals of Eugenics. 7 (2): 179–188.
It contains 150 instances of iris plants:
50 Iris Setosa,
50 Iris Versicolour,
50 Iris Virginica.
Each instance is characterized by:
its sepal length in cm,
its sepal width in cm,
its petal length in cm,
its petal width in cm.
Dataset can be used for either clustering purposes
or classification ones.