You can legally take cuttings from anything you grow from seed. The issues come when you are taking cuttings from mature plants - one, that they are your own or you've received permission; two, they are not patented plants and three, you know the correct botanical and cultivar name.

The key to the propagating of mature plants is that they are not patented. Patented plants CANNOT be propagated (other than by seed) without permission and licensing by the patent holder or his rep. And a good many patented plants are sterile or will not come true from seeds so that's a very poor option :-)