De Plantatione

For, as in the case of woman and every animal of the female sex, fountains of milk spring up in them when they are about to bring forth, in order that they may supply the offspring that is born of them with necessary and suitable food; so in a similar manner God has assigned to the earth, which is the mother of all terrestrial animals, all the different species of plants, in order that the animals produced by the earth may have such food as is akin to them, and not alien from their natures.