Kant: How is the Science of Nature Possible?

"...nature is the complex of all the objects of experience." (section 16)

Immediately after reading this I thought that not everything in nature comes from experience. Many things are either a figment of our imagination or grown naturally. Then Kant went on to say this:

"And with this only are we now concerned, for besides, things which can never be objects of experience, if they must be known as to their nature, would oblige us to have recourse to concepts whose meaning could never be given in concreto (by any example of possible experience)." (section 16)

Then I knew that Kant was saying exactly what I was thinking. Although many things are from experience there are even more things that are not from experience. Mant creatures, plants, and organisms are not from experience.