"Cross section of a portion of the blade of a leaf, showing upper epidermis at a, lower epidermis at b, palisade parenchyma at c, spongy parenchyma at d, and tracheids from the end of a vein at e." -Stevens, 1916

Leaf Epidermis

"Cross section of a portion of the blade of a leaf, showing upper epidermis at a, lower epidermis at…

"Diagram to show the radial flow of water in pine wood, from the tracheids of the late growth of one year into those of early growth of the succeeding year." -Stevens, 1916

Water Flow in Pine

"Diagram to show the radial flow of water in pine wood, from the tracheids of the late growth of one…

"Diagram indicating by arrows how the water in the tracheids of pine passes longitudinally from one tracheid to another." -Stevens, 1916

Water Flow in Pine

"Diagram indicating by arrows how the water in the tracheids of pine passes longitudinally from one…