50 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



ists still remains to be settled. The species does not adhere well to paper, and would 

 probably, at first sight, be referred by collectors to Chcetomorpha rather than to Ehizo- 

 clonium. 



CLADOPHOEA, Kutz. 



(From KAadog, a branch, and (popeu, to bear.) 



Filameuts firm, not gelatinous, branching tlirougliout. 



A genus including the greater part of the branching Chlorosporew, which are found 

 both in salt and fresh water. It differs from Ulothrix and Chcetomoiyha in having 

 branching filaments, and from Ehizodonium in having well-developed branches and 

 not mere rhizoidal growths. The species abound on rocks and in tide-pools, as well 

 as in ditches and shallow bays along the shore, and usually grow in tufts. Some of 

 the species, however, especially those growing in brackish ditches, at maturity form 

 dense layers upon the surface of the water or on the bottom. The number of described 

 species of the genus is immense, but, in all probability, a great part are not distinct. 

 It is at present impossible correctly to refer the New England si^ecies to European 

 forms, since European botanists by no means agree as to their own species, and there 

 has been a tendancy on the part of algologists of different countries to ignore the 

 species of other countries in studying their own. The principal specific character is 

 the mode of branching, which, in the present genus, is at best an uncertain mark. The 

 young and old plants of the same si^ecies often differ very much in the appearance of 

 the branches, so that the habit varies at different seasons. When old, some species 

 are usually torn from their attachments and washed ashore in large masses, and, in 

 this battered condition, it is often impossible to recognize the species, or perhaps even to 

 distinguish the specimens from RMzoclonium species. Unfortunately, names have been 

 given to the battered forms until there i» such a labyrinth of synonyms that one is 

 tempted to reject all but a few well-marked species. In the present instance we have 

 attempted merely to comjiare our specimens with those in the Algse Danmonienses, 

 the Algues Marines du Finistere, the Algae ScandinavicsB of Areschoug, and with 

 specimens received from Dr. Bornet, M. Le Jolis, Dr. Kjellman, and Dr. Wittrock. It 

 is to be hoped that some responsible algologist will undertake the revision of this 

 much-abused genus. 



Subgenus SPONGOMORPHA, Kutz. 



Plants spoDgy, at least towards the base, owing to the interlacing of 

 the branches, some of which are strongly recurved and rhizoidal. 



C. ARCTA, (Dillw.). {Cladophora arcta, Phyc. Brit., PI. 135.) 



Filaments slender, two to eight inches long, tufted and densely matted 

 at base, becoming free and divergent above, color a bright green j branches 

 near the base strongly recurved and interlaced, upper branches erect or 

 appressed, numerous, opposite or scattered, apices obtuse ; cells at base 

 about twice as long as broad, cells of upper i)ortion several times longer 

 than broad, average diameter of cells about .08™°\ 



On rocks between tide marks. Winter and spring. 



Common along the whole coast j Europe. 



One of the few species which are recognized without difficulty, although it varies 

 considerably in aspect at different seasons. When young the filaments are but slightly 

 matted together, except at the very base, and the species is then the C. vaucliericeformis 



