I. M. Johnston

I. M. (Ivan Murray) Johnston (1898–1960), was a United States botanist. He studied at Pomona College in Claremont, California and at Harvard University. His plant collections are housed in the Rancho Santa Ana Botanic Garden, in Claremont, and in the Gray Herbarium of Harvard University.

His areas of interest, were, among others: Pteridophytes, Spermatophytes

...
Wikipedia