THE GUESTS OF THE MAYFLOWEK. 19 



over is evidently tending strongly to a more perfect dioecism 

 When it finishes its task of eliminating the filaments as it has 

 the anthers of the stamens in many of the pistillate blossoms, and 

 gets rid of the superfluous pistils of the staminate blossoms, it will 

 accomplish its purposes of reproduction with less waste than at 

 present. 



A plant in the condition of the arbutus may be said to be in a 

 certain sense at a " parting of the ways/' To attain the end of 

 cross-fertilization the carrying of the pollen from the stamens 

 of one plant to the pistils of another two methods appear to be 

 open to it. It may, and in the case of many of the Blueberry 

 Hill specimens evidently has, become more perfectly dioecious by 

 aborting the stamens on some plants and the pistils on others ; or 

 it might become dimorphous by developing perfect sexual organs 



FIG. 2. VARIATIONS OF THE MAYFLOWEK. 



in each blossom and having them at different heights that is, 

 having the stamens in one plant reach the mouth of the corolla 

 and the pistil reach only half way to the mouth, while in another 

 having the pistil long and the stamens short. The tendency 

 toward dimorphism or trimorphism is shown by the varying 

 lengths of the styles and filaments. 



The blossoms of the common asparagus of our gardens show 

 by their structure that they are in a transition stage somewhat 

 similar to that of the arbutus. The staminate blossoms have 

 rudimentary pistils and the pistillate blossoms rudimentary sta- 

 mens, and sometimes a blossom is found which has both sets of 

 organs in good condition a reversion to an earlier condition of 

 the plant. 



The partridge berry,* a plant which has to contend with 

 much the same external conditions as the arbutus, living in simi- 

 lar situations and remaining close to the ground, has adopted 



* Mi!chella repens. 



