14 THE AMERICAN NATURALIST [Vol. XLIX 



Epilobium angusti folium. Many of the grains of pollen 

 are light colored and devoid of the protoplasm which 

 gives a dark appearance to the sound grains. Fig. 7 illus- 



trates a single stamen under a high degree of magnifica- 

 tion. The characteristic layers of the wall of the anther 

 sack, described comparatively and in detail in the classic 

 memoir of Chatin, can readily be distinguished. Within 

 lie the pollen grains. Clearly only a few of these are fully 

 developed and possess normal protoplasmic contents. 

 The greater number are shrivelled and empty. Judged 

 from the generally accepted canon of the abnormalities of 

 hybrids, 0. biennis is of hybrid origin. This view of its 

 nature is in harmony with its wide degree of inconstancy 

 throughout its very extended range. This feature is 

 doubtless responsible for the fact that the genus (Enoihera 

 is at the present time undergoing considerable elaboration, 

 on the part of systematists. I have satisfied myself that 

 the pollen peculiarities of 0. biennis are uniformly pres- 

 ent in specimens collected hundreds of miles apart, from 

 the Province of Ontario, the shores of the Gulf of St. 



