 His personal herbarium totaled approximately 25,000 species and is now at the University of Michigan Herbarium.He wrote numerous articles and several books including "Elements of Philippine Agriculture" (1908), "The Coconut" (three editions, 1914, 1921, and 1931), "Rice" (1924), "Fern" (1964) and "Natural Conduct" (1928), a book on practical ethics.In a letter during his final months, a friend C.V. Morton wrote, "You have the consolation of knowing that your name is in constant use by fern students the world over."