vi CONTENTS 



Shull, George Harrison. The duplication of a leaf-lobe factor 



in the shepherd 's-purse 4-7 



SiNNOTT, Edmund W. Isolation and specific change 444 



Smith, Erwin F. The relations of crown-gall to other over- 

 growths in plants 44^ 



Stone, George E. Contact stimulation 454 



Stout, A. B. Duplication and cohesion in the main axis in 



Cichorium Intyhus 480 



Taylor, Norman. A quantitative study of Raunkiaer's growth- 

 forms as illustrated by the 400 commonest species of Long 



Island, N. Y 486 



Trelease, William. The ancient oaks of America 492 



True, Rodney H., and Harvey, R. B. The absorption of cal- 

 cium salts by squash seedlings 502 



White, Orland E. Inheritance studies on castor beans 513 



