FLOWERS OF ACER SACCHARINUM, 203 



Physiological Considerations. — ^Wherever a pistil of 

 any considerable size is found in a staniinate flower it apjjears 

 qnite regularly to be accompanied by a dwarfing of the stamens, 

 or at least their e-rowth is retarded to such an extent that thev 

 do not scatter their pollen until some time after anthers in ad- 

 joining flowers have burst. Such hermaphrodite flowers often 

 mature their anthers from one to three days later. I!y tliat time 

 tlic stigmas have had every oj)portnuity to become coxcvcd witli 

 pollen fi-oui other flowers. 



To ascertain whether pistils found in staniinate flowers are 

 ever really functional, several sucli hermaphrodite flowers were 

 marked and left on the trees. Because of the diflicultv of findini>' 

 these minute structtires without detaching or injuring the flower, 

 only eight such specimens were located. These were marked so 

 tliat the flowers might be readily found again. These flowers 

 were then examined every few days, and it was found that five 

 flowers out of the eight produced seeds at the same time as did 

 the pistillate flowers on the same tree. This proved conclusively 

 that some of the pistils found in staniinate flowers are still func- 

 tional. 



To determine whether such hermaphrodite flowers are cap- 

 able of self-fertilization, furtlier observations were made. Small 

 pieces of court-plaster were rolled wp into hollow cones, and with 

 these cones or caps several lierniaphrodite "staniinate" flowers 

 were covered. AYlien a staniinate flower was found containing a 

 pistil, the stamens of the other four flowers in that fascicle were 

 taken out without in any way disturbing the flower to be experi- 

 mented upon. This taking out of other flowers served also to give 

 more room for growtli within the fascicle, should the flower fer- 

 tilize itself and distend its pistil before the removal of tlie cap a 

 week later. After these amputations, the little cap was placed 

 over the entire fascicle with sufficient care to avoid any ])ossi- 

 bility of inflicting a mechanical injury to the sole remaining 

 flower. After the cap was adjusted it was securely fastened by 

 passing a narrow band of adhesive tape entirely around the 



