BOT.-VOL. II.] HUS—PORPHYRA. 205 



possesses a pronounced aureole around the point of attach- 

 ment, often one centimeter in diameter. 



The writer has had an opportunity to examine a large 

 number of specimens of P. -perforata collected at numerous 

 localities on the shores of the Pacific Ocean, but has up to 

 this time failed to encounter a single distromatic specimen. 

 A thorough examination of the fronds left no doubt as to 

 the purely monostromatic nature of the species, all consist- 

 ing in the purely vegetative part of but a single layer of 

 cells. 



The thickness of the frond varies from 40 to 140^1, the 

 difference in thickness being oftener due to a greater 

 amount of jelly than to a difference in the height of the 

 cells. The cells in the lowest part of the frond are usually 

 square or nearly so, but more towards the tip they are from 

 one and one-half to two and one-half times as high as 

 broad. 



Porphyra -perforata is monoecious. Patches of sporo- 

 carps and antheridia occur here side by side, usually alter- 

 nating; but not a single instance has been met with, where 

 the antheridial and sporocarpic cells were intermixed, such 

 as we meet with in P. aniplissima, or where one-half of the 

 cell formed antherozoids and the other half carpospores, 

 such as described by Janczewski (1873) for P. leucosticta. 

 The frond is often nearly entirely sporocarpic or antherid- 

 ial. Vegetative cells are sometimes encountered among 

 the sporocarps but never among the antheridia. There are 

 also cases where one or several of the divisions of the cell 

 in the formation of the sporocarp have not developed, so 

 that but one or more have formed spores, while the others 

 are to all appearances dead. The walls of such a cell are 

 thickened, the contents are hyaline and of a deep yellow 

 color, which sharply contrasts with the dark violet tinge of 

 the carpospores, and the unchanged, granular contents of 

 the vegetative cells or of the monospores. Some instances 

 have been noted where the sporocarps occurred in long 

 narrow patches, instead of in the broader patches usually 

 found. 



(3) December 27, 1901. 



