1922] 



PAYSON — STUDY OF THELYPODIUM AND ITS IMMEDIATE ALLIES 243 



south from there. The plant that is supposed to represent the 

 most ancient type of "Thelypodiopsis" is Thelypodium ambigu- 

 um Wats. It is not here transferred to the segregate genus be- 

 cause the author does not yet wish to recognize "Thelypodiopsis" 

 as worthy of generic rank. Thelypodium ambiguum must be 

 associated with "Thelypodiopsis" elegans (Jones) Rydb. and 



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Fig. 1. Phylogenetic chart of the species of Thelypodium. 



