338 W. A. Setchell — Classification and Geographical 



Subtribe 1. Laminarieae. — To this subtribe belong the three 

 genera Chorda^ Saccorhiza, and Laminaria^ They agree in possess- 

 ing a frond which is neither ribbed, perforated, nor with bullate 

 swellings scattered over it and whose transition-place is perfectly 

 plane and unmodified. 



Chorda^ Stackh. We have two species of Chorda which are 

 well known. They both differ very much in habit from the other 

 kelps in possessing long cylindrical fronds which arise from a dis- 

 coidal hold-fast. The fronds are hollow with diaphragms at irregu- 

 lar intervals. The fronds in both species are covered with hairs, 

 which in C. jilum (L.), Stackh. are more scanty and colorless, while 

 in C. tonientosa, Lyngb., they are plentiful and possess abundant 

 chromatophores. One or two other species are described, but they 

 are little known. 



It has been customary for the last fifteen years to place these 

 species among the Laminariace^e, on account of their unicellular 

 paraphj^ses and unilocular sporangia covering the surface of the 

 frond. But Reinke^ dissents from this view and places them in a 

 special sub-family Chordege (under Phseosporeae) near to the Scyto- 

 siphonese, on account of the cylindrical thallus and the occupation 

 by the zoosporangia and the paraphyses of the whole surface. 



Chorda resemble Scytosipho7i very much in habit and in this, 

 differs from the other members of the Laminariaceae, all of which 

 possess a distinction between stipe, blade, and hold-fast. It differs 

 from Scytosiphon in its unilocular sporangia and more abundant 

 unicellular paraphyses and in these details it resembles more closely 

 the ordinary kelps. But the paraphyses lack the hyaline appendage 

 so characteristic of nearly all the Laminariacese. In this however, 

 it agrees with the species of Saccorhiza whose paraphyses are 

 almost identical in structure with those of Chorda. It seems best 

 to the writer therefore, to retain Chorda among the Laminariacese, 

 for the present at least. ^ 



Saccorhiza^ DelaPyl. — There are two species of this genus that 

 are well known and two or three species that are very uncertain. 



^ Prof. Kjellman (Uiiclersokning af nagra till slagtet Adenocj'^stis, Hook. fil. et Harv. 

 hanforda Alger, in Bihang till k. Svenk. HandL, Bd. xv, Afd. Ill, No. 1, 1889), has 

 referred the type of the genus Adenocystis, A. Lessonii, Hook. fil. et Harv. to the 

 Laminariaceoe, placing it near Chorda. The writer has not been able to examine spe- 

 cimens of this type. 



^ Atlas Deutscher Meeresalgen, Heft 2, p. 41, 1891. 



3 Cf. also Setchell, Proc. Am. Acad., vol. xxvi, pp. 211-212, 1891 



