See De Stendhal, Histoire de la Peinture en Italie, p. 143, for this story.
In the Treatise on Painting, da Vinci argues strongly against isolating man. He regarded the human being as in truth a microcosm to be only understood in relation to the world around him, expressing, as a painter, the same thought as Pico. (See Vol. II., Revival of Learning, p. 35.) Therefore he urges the claims of landscape on the attention of artists.
I might refer in detail to four studies of bramble branches, leaves, and flowers and fruit, in the royal collection at Windsor, most wonderful for patient accuracy and delicate execution: also to drawings of oak leaves, wild guelder-rose, broom, columbine, asphodel, bull-rush, and wood-spurge in the same collection. These careful studies are as valuable for the botanist as for the artist. To render the specific character of each plant with greater precision would be impossible.