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THE AMERICAN NATURALIST [Vol. XLIX 



photographically the floral organization of Epilobium 

 hirsittum, as seen in transverse section of the bud just 

 about to open. The illustration shows the floral envelopes 



and the stamens, together with the pistillary portion of the 

 flower, the latter being somewhat displaced in the figure 

 and cut through the region of the style. The long hairs 

 characteristic of the calyx of this species have been 

 trimmed off, for the purpose of facilitating photo- 

 mechanical reproduction. As in the two illustrations 

 above, the anther sacks are the most significant feature. 

 Even with the low magnification employed for the purpose 

 of illustrating the whole flower, the pollen grains in the 

 loculaments of the anthers are easily discernible and pre- 

 sent a striking contrast to those of E. angustifolium, in the 

 respect that they are in groups of tetrads. Some of the 

 groups are partially or wholly made up of individual 

 grains without protoplasmic contents, which are smaller 

 in size than the normal grains. Fig. 5 shows one of the 

 anthers much more highly magnified. The anther walls, 

 cavities and the pollen grains are now clearly distinguish- 



