[Lancaster, Pa.,Press of the New Era Print. Co.]1898. | New York Botanical Garden, LuEsther T. Mertz Library

monograph by Per Axel Rydberg, published in 1900

New York1900

New York,1901 | New York Botanical Garden, LuEsther T. Mertz Library

Fort Collins, Col., Experiment Station, 1906.

Libro de botànica por Per Axel Rydberg

1903 flora by John Kunkel Small