Proceedings of the Biological Society of Washington - Smithsonian Institution (Biological Society of Washington, 1990)

Smithsonian contributions to botany - Smithsonian Institution (Smithsonian Institution Press, 1999)

Smithsonian contributions to botany - Smithsonian Institution (Smithsonian Institution Press, 1999)

Smithsonian contributions to botany - Smithsonian Institution (Smithsonian Institution Press, 2012)

Smithsonian contributions to botany - Smithsonian Institution (Smithsonian Institution Press, 2012)

Smithsonian contributions to botany - Smithsonian Institution (Smithsonian Institution Press, 2012)