1902J Collins, — Marine Cladophoras of New England 113 



indistinct, and their identity with European types is unsettled. 

 Harvey 1 credits to the New England coast n species of the 19 

 which he describes for North America. Farlow 2 gives 14 species 

 and 3 varieties. A familiarity for quite a number of years with 

 the plants as they grow along our shore, has led the writer to con- 

 clude that some changes should be made in these lists, and the 

 present paper is intended to give a revised list, with the principal 

 characters ; 17 species, 6 varieties and 3 forms being included. 



In determining a specimen, a good plate is better than any 

 description, and an authentic specimen in good condition is better 

 than any plate. References have therefore been made in the follow- 

 ing pages, under each species, to such books and sets of exsiccatae 

 as are likely to be found at the principal botanical and educational 

 centers, and will be of most assistance to the student. The refer- 

 ences to Harvey, Lejolis and Hauck have in almost all cases been 

 verified by authentic specimens in the Farlow Herbarium at Cam- 

 bridge and in the writer's collection. In the case of the older 

 authors, such as Roth and Dillwyn, authentic specimens have not 

 been obtainable, but wherever there seems to be reason for doubting 

 an identification, the doubt has been indicated. Plate 36, accom- 

 panying this paper, is intended to supplement the descriptions, 

 chiefly as to the lesser branches of the various species. The figures 

 should be considered as schematic, rather than as accurate drawings 

 to scale. 



Of the three subgenera, Aegagropila, Spongomorpha and Eucla- 

 dophora, the first is not represented by any marine species in this 

 region. Spongomorpha, with plants densely matted in the lower 

 part or throughout by special hooked branches or by descending 

 rhizoidal filaments, and Eucladophora, which lacks these special 

 branches, are both common. A not absolutely accurate, but per- 

 haps useful key to our species, may be found in the following : 



Artificial Key to the New England species of Cladophora. 



Filaments matted together by descending rhizoidal filaments or hooked 



branches in the older parts. Spongomorpha. a 



Filaments free or more or less intertwisted, but not matted together by 



special branches. Eucladophora. d 



1 Nereis Boreali- Americana, part 3, Smithsonian Contributions to Knowledge, 

 Washington, 1858. 



2 Marine Algae of New England and adjacent coast, Report of the U. S. Fish 

 Commission for 1879, Washington, 1881. 



