i 
636 J. ARTHUR HARRIS 
such as would be readily accepted by a careful geneticist. Further- 
more, both of these assumed parent species have simple inflorescences. 
S. Vanhouttei is horticulturally such a splendid form that it would 
be well worth while for some unoccupied geneticist to attempt further 
crosses in this group of Spiraeas. 
Station for Experimental Evolution, 
Cold Spring Harbor, N. Y. 
