PLATE 21 



Leaves of I'o/nilns trichocarpa for Comparison with 

 Populus alexanderi Dorf 



Figs. 1—11. Typical leaves of Populus trichocarpa from the mountains of 

 southern California, collected from trees below the yellow pine forest zone. 

 They compare favorably with the leaves of Populu.s alexanderi Dorf in the 

 Verdi flora (see pi. 19). 



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