De Plantatione

Very naturally and appropriately therefore, all earth will not be dissolved by all water, which the bosom of the earth contains, nor will fire be extinguished by air, nor again will air be burnt up by fire, since the divine law establishes itself as a boundary to all these elements, like a vowel among consonants, so that the universe may, as it were, be harmonious in concert with the music expressed by letters; persuasion, by its own authority, putting an end to the threatening conflicts of contrary natures.

Thus then the plant which bears all things was rooted, and when it was rooted was made strong. But of the particular plants, and those of smaller growth, some were moveable, so as to have their places changed; and some were made so as, without any such change, to stand steadily in the same place.