186 University of California Publications in Botany [Vol. 8 



On various algae in the middle and upper littoral belts. Alaska to 

 California. 



Kuetzing, Phyc. Germ., 1845, p. 205 (at least as to the plant of 

 Dillwyn) ; Farlow, New Eng. Alg., 1881, p. 49; Setchell and Gardner, 

 Alg. N.W. Amer., 1903, p. 223; Collins, Green Alg. N. A., 1909, 

 p. 328. Conferva tortuosa Dillwyn, Brit. Conf., 1805, p. 46, pi. 46 ; 

 Harvey, Phyc. Brit., vol. 1, 1846, pi. 54 A, Chaetomorpha tortuosa 

 Kuetzing, Spec. Alg., 1849, p. 376 ; Harvey, Ner. Bor.-Amer., part 3, 

 1858, p. 88, pi. 46 B. 



Kuetzing has described two plants, both founded, in the final 

 analysis, upon Conferva tortuosa Dillwyn. One of these plants he 

 bases directly upon Dillwyn 's species and refers it to Rhizoclonium 

 (1845, p. 205; 1849, p. 384). It is credited by Kuetzing to the North 

 Sea. Kuetzing gives ^7o'"'-%o"'' as the diameter of his Rhizoclonium 

 tortuosum which approximates 32ja to 35fi. The Conferva tortuosa 

 J. Ag. (1842, p. 12) which is the C. tortuosa C. Ag. (1824, p. 98) 

 and which, in turn, is founded, as to name at least, on C. tortuosa 

 Dillw., is referred by Kuetzing (1849, p. 376) to the genus Chaeto- 

 morpha as Chaetomorpha tortuosa and the diameter of the filaments 

 is given as /^s^'-zio"', or approximately 46/a to 56ju,. It is restricted 

 by Kuetzing to the Mediterranean and Adriatic Seas, 



Dr. Anna Weber-van Bosse has kindly allowed us to examine the 

 specimens in Herbarium Kuetzing under the names of Rhizoclonium 

 tortuosum and Chaetamorpha tortuosa. There are three of the former, 

 from the Faeroes, England and Cherbourg respectively. They all 

 seem to be R. tortuosum in the sense in which we use the name : The 

 specimen of Chaetomorpha tortuosa from the Kuetzing collection is 

 from Nice and while it resembles fairly closely the Kuetzing specimens 

 of R. tortuosum, it has much thicker walls and possibly may be found 

 to belong to another species. 



"We feel convinced of the likelihood of Conferva tortuosa Dillw. 

 being the coarse, crispate plant which has been described by Harvey 

 (1846, pi. 54 A) as Conferva tortuosa and (1858, p. 88) as Chaeto- 

 morpha tortuosa and finally by Farlow (1881, p. 49) as Rhizoclonium 

 tortuosum. 



As we understand this species, which is not common on our coast, 

 it forms woolly skeinlike or loose ropelike masses of a dark green color 

 on other algae in the littoral belt of exposed coasts. The filaments 

 are rigid, harsh to the touch and crispate or contorted. In diameter 

 its filaments exceed those of both R. riparium and R. implexum by 



