10 



THE AMEBIC AN NATURALIST 



[Vol. XLIX 



fire weed, which by contrast to many of the other Epilo- 

 biums, is so constant and distinct that it is frequently 

 referred to a separate genus, Chamcsnerion. This species 

 shows its most marked distinction from other species of 

 Epilobium {Epilobium proper) in the fact that its pollen 

 grains are separate and not in tetrads, as is the case in 

 other common species. Fig. 2 reproduces photograph- 



ically a transverse section of a mature flower bud of 

 E. (Chamcenerion) angustifolmm. On the outside are 

 seen the floral envelopes, two in number, composed, as is 

 the rule in the Onagraceae, of four parts each. Within lie 

 four stamens represented by their anther sacks and inter- 

 nal to these are four stigmas representing the carpellary 

 or ovarial portion of the flower. The photograph is on a 

 sufficient scale of magnification to show the pollen grains 

 in the loculaments or cavities of the anthers. Obviously 

 the pollen is very uniform and perfect in its development. 

 Fig. 3, likewise photographic, illustrates the organization 

 of the pollen as viewed with a much higher magnification 

 of the microscope. Although some of the grains are only 



