360 TUFTS COLLEGE STUDIES, VOL. II, No. 3 



Forma PULVINATA Foslie, 1890, p. 130; Cladophora arcta 

 forma pulvinata P. B.-A., No. 918. Filaments short, of uni- 

 form length, forming level-topped pulvinate masses. Alaska. 



Northern Europe. 



5. S. saxatilis (Rupr.) nov. comb. ; Cladophora saxatilis 

 Setchell and Gardner, 1903, p. 223; P. B.-A., No. 921. Fronds 

 dense but not much matted together; filaments 80-120 /x, 

 diam., about the same diam. throughout, cells below 1-3 diam. 

 long, above 3-6 diam. ; terminal cell sometimes 10-12 diam. ; 

 branching di- trichotomous, with occasional lateral branches, 

 divisions erect, somewhat acute or tapering, but with rounded 

 tip ; older parts with descending rhizoidal filaments, about half 

 the diam. of the filaments from which they spring, and with 

 longer cells, sometimes 10-12 diam. long. Alaska to Wash. 



Kamtschatka . 



Varying considerably in size of filaments, length of cells, 

 erect or patent branches, but on the whole with longer cells than 

 most of the species of Spongomorpha. The branches increase 

 little if any in size towards the end, and the terminal cell is not 

 sharply truncate. The four species of Ruprecht, 1856, Con- 

 ferva Chainissonis, C. Mertensii, C. viminea and C. saxatilis^ 

 seem to be merely varieties, forms or states of growth of one 

 species, C. saxatilis representing stouter or older forms, C. Cha- 

 missonis more delicate ; the two other species range between. 

 Little could be known from Ruprecht's short descriptions, but 

 authentic specimens in Herb. Farlow justify the present 

 arrangement. 



Var. Chamissonis (Rupr.) nov. comb.; Cladophora Cha- 

 missonis Harvey, 1858, p. 75 ; P. B.-A., No. 920. Filaments 

 40-60 /x diam., cells 3-4 diam. long, nodes constricted; cells 

 slightly shorter towards the base. Alaska to Wash. 



Kamtschatka . 



Smaller and more delicate than the type, but not otherwise 

 distinct. 



6. S. SPINESCENS Kiitzing, 1849, p. 418; 1854, PL LXXV, 

 fig. 2 ; Cladophora arcta var. centralis P. B.-A., No. 721. Fila- 

 ments about 80 /u below, i oo /A at tip ; cells j^-i diam. long below, 

 2 diam. long at tip ; normal erect, somewhat obtuse branches 

 abundant ; also patent and acute branches, either short and 

 spine-like, or long, hooked, revolute and circinate, uniting the 

 filaments into branching rope-like tufts ; descending rhizoidal 

 branches less common. Fig. 126. Me. to Mass. ; Alaska. 



Northern Eiirope. 



