I demand of you, and of the whole world, that you show me a generic character... by which to distinguish between Man and Ape. I myself most assuredly know of none.

Yet man does recognise himself [as an animal]. But I ask you and the whole world for a generic differentia between man and ape which conforms to the principles of natural history, I certainly know of none... If I were to call man ape or vice versa, I should bring down all the theologians on my head. But perhaps I should still do it according to the rules of science.

The plant kingdom covers the entire earth, offering our senses great pleasure and the delights of summer.

Nature does not proceed by leaps.

If you do not know the names of things, the knowledge of them is lost, too.

A practical botanist will distinguish at the first glance the plant of the different quarters of the globe and yet will be at a loss to tell by what marks he detects them.

Stones grow, plants grow, and live, animals grow live and feel.