298 MINNESOTA BOTANICAL STUDIES. 



found in the somewhat loosened, fruit-bearing section of the 

 thallus appearing in great numbers in the central part of the 

 cortex. A short, two or more celled, many forked, small second- 

 ary side-branch of a filament forms an auxiliary cell from an 

 end cell. Near the auxiliary cell is developed a three-celled 

 carpogonial branch bent in shape of a hook. The gonimoblast 

 apparently arises from the fecundated auxiliary cell, branches 

 profusely, at times towards the center, into the somewhat loos- 

 ened tissue of the inner layer. The branches of the gonimo- 

 blast creep between the rows of cells of the sterile tissue, often 

 fusing with these cells, and finally the end cells develop into 

 spores. 



The fruit-body is an irregular mass of interlacing fibers of 

 which the lower, stronger sections of the branches stand out 

 plainly, with numerous spores irregularly massed in the inter- 

 stices. The cystocarp, without a special protective layer, is 

 sunk in the locally, slightly thickened thallus. It protrudes 

 slightly to one side of the thallus near the short spiny point of 

 a branch. The fruit wall formed by the local thickening of the 

 cortex of the thallus does not show a pore. 



The same authors describe the reproductive organs of the 

 Gigartinaceae as follows : Reproduction occurs both sexually 

 and non-sexually. The tetraspores are strewn over the surface 

 under the outer cortex or in many irregular groups and then 

 sunk in the inner cortex of the thallus, or arranged in project- 

 ing nemathecia. The sporangia usually divide transversely but 

 they also divide obliquely (Endocladid). 



Antheridia are spread over the upper surface of the thallus, 

 sometimes in the form of small, cup-shaped capsules, opening 

 outwards, and sunk in the outer cortex of the thallus. 



The carpogonial branch develops from a lateral branchlet of 

 a primary branch. The carpogonial branch is three-celled, 

 bent inwards like a hook, and connected with the swollen auxil- 

 iary cell, rich in contents. The fecundated auxiliary cell grows 

 inwards and develops the gonimoblast branches. The end cells 

 of these branches are transformed into spores. 



Endocladia hamulosa (Ruprecht) J. Ag., described in De- 

 Toni's Sylloge Algarum, seems to differ from E. muricata only 

 in the position of the cystocarps. " E. hamulosa seems to 

 differ from E. muricata only in having the cystocarps at the 

 bases of the ramuli, while in the latter species they are simply 



