This collection includes the correspondence (four letters, 1946) of Esau and Gilbert M. Smith (1885–1959) of Stanford University, concerning a possible arrangement between them for a book on the morphology of angiosperms, based on Esau's revisions of Smith's notes. The book that did result was Esau's Plant Anatomy (New York, Wiley, 1953). The collection also contains undated notes (6 typescript pages) on morphology.