Alberti Magni De Vegetabilibus Libri VII

...nature is most effective for the generation of plants and is explained at greater length IV §. 48—84.

Plants are generated either by seed, or by putrefaction—in which the power of the stars acts to generate parts—or by grafting I §. 182—187, IV §. 47, 85—93, V §. 10.

They require water and moisture as food for generation IV §. 85—87.

Generation from seed or from the power of the stars, beyond matter, requires seven things: namely, heat to act, which is threefold—that of the celestial circle, the place, and the seminal matter; and a threefold moisture to provide the matter—of the seed, the place, and the rains, to which a seventh, suitable air, is added V §. 2—5. It is necessary for the matter to possess elements mixed in proportion, a vegetable soul, and the correct quantity and shape, just as is found in the seed V §. 6—9.

Chapter VII.

Albertus labored much on the chemical reasons which he posits for the nourishment of plants, the generation of colors and juices, and the variety of their forms and medicinal powers. He had nothing, however, from which to draw except the Aristotelian doctrine of digestion and composition from the four elements—which you will find explained by Meyer in section VI of our Praelibanda Introductory matters/preliminaries. Relying upon this,