eI 5 Fos igh NN i TRU AR A A 
dun ee 4 
1921] 
PAYSON—MONOGRAPH OF THE GENUS LESQUERELLA 125 
of origin, since there the genus would have existed for the long- 
est period of time. In the map showing distribution of species 
Fig. 4. Geographical distribution of the species of Lesquerella in North America 
showing relative specific condensation. 
in North America it is evident at once that the greatest specific 
concentration occurs in central Texas. It is quite possible, 
however, that the point of greatest concentration might coincide 
