Man has long learnt to make use of this law of metamorphosis in the plant for what is called doubling the flower of a certain species. Such a flower crowds many additional petals within its original circle, and these petals are nothing but metamorphosed stamens; this, for instance, is the difference between the wild and the cultivated rose. The multitude of petals in the latter is obtained by the transformation of a number of the former's innumerable stamens. (Note the intermediate stages between the two, often found inside the flower of such plants.)