592 University of California Publications in Botany [Vol. 8 



Dumortier, Comm. Bot., 1822, p. 72 (Me Pfeiffer) ; Kylin, Stud, 

 iiber Algenfl. der Schwed. Westkiiste, 1907, p. 97. 



The single genus Chorda', clearly a member of the Laminariales, 

 but differing from all the other genera of the order in its hollow 

 cylindrical frond, is taken to represent a distinct family. 



40. Chorda Stackh. 



Fronds arising from a small disk-shaped holdfast, unbranched, 

 cylindrical, solid below, hollow above, the cavity separated by cross- 

 partitions into many chambers, color olive brown, growth intercalary 

 near the base ; median tissue of the hollow portion composed of longi- 

 tudinally elongated cells, hexagonal in cross-section, firmly united, 

 lined with delicate, loose filaments which unite to form the cross-parti- 

 tions at intervals; the outside of the median tissue is clothed with 

 unicellular paraphyses, hairs and zoosporangia ; reproduction asexual 

 by unilocular zoosporangia. 



Stackhouse, Physiol. Observ., m Ner. Brit., 1797, p. xvi. 



The type of the genus is the Fuous Filum of Linnaeus (Sp. PL, 

 1753, p. 1162). The type locality is unknown. 



Chorda Filum (L.) Lamour. 



Fronds gregarious, several at times arising from the same confluent 

 base, cylindrical, sometimes spirally twisted, slightly tapering at the 

 base and at the apex, from 3 dm. to 4 m. long, 2-5 mm. diam., 

 lubricous, when young clothed with a dense growth of hyaline or 

 yellowish colored hairs ; paraphyses unicellular, densely crowded, 

 clavate, slightly longer than the zoosporangia and nearly obscuring 

 them above ; unilocular zoosporangia oblong to ellipsoidal, 30-50;u, 

 long, 10-15/i, wide; plurilocular gametangia 35-40/i- wide. 



Growing on stones in the upper sublittoral belt. From Port 

 Clarence, Alaska, to the Straits of Juan de Fuca. 



Lamouroux, Essai, 1813, p. 26 ; Saunders, Alg. Harriman Exp., 

 1901, p. 424; Setchell and Gardner, Alg. N.W. Amer., 1903, p. 254; 

 Reinke, Atlas, 1889, p. 35, pis. 26, 27, 28. Fiiciis Filum Linnaeus, 

 Sp. Plant., 1753, p. 1162. 



There is little to be said under Chorda, except to note that it is a 

 plant of the colder waters and of which we have seen specimens from 

 our coast collected at Port Clarence, Safety Harbor, near Cape Nome, 



