Per Axel Rydberg

Flora Of The Black Hills Of South Dakota

Flora Of The Sand Hills Of Nebraska

A Monograph Of The North American Potentilleae

Catalogue Of The Flora Of Montana And The Yellowstone National Park (1900)

Scandinavians Who Have Contributed To The Knowledge Of The Flora Of North America, Volume 1907, Part 1

A Monograph, North American Potentilleae (Classic Reprint)

Flora Of The Black Hills Of South Dakota