1925] Setchell-danhu r: M< la noph yceae 501 



(Flor. du. Fin., p. 166). It is credited only to the extreme northern 

 part oi' our region. All of the specimens previously reported within 

 our territory are sterile and there is the greatest doubt as to their 

 identity, both generic and specific. Two species have been assigned to 

 our coast, but it is doubtful whether they are correctly referred. We 

 can only list these two species with description and comment. 



Key to the Species 



Thallus nearly circular in outline, up to 3 dm. diam 1. L. fatiscens (p. 501) 



Thallus irregularly elongated or almost linear in outline 2. L. lignicola (p. 501) 



1. Lithoderma fatiscens Aresch. 



Thallus broadly expanded, nearly circular in outline, up to 3 dm. 

 diam., scarcely 1 mm. thick, smooth, shining when wet; the basal 

 layers of cells minute, and somewhat polyhedral, vertical filaments 

 12-18/x diam., 8-12 cells long; gametangia small, cylindrical or oval, 

 formed by transformation of terminal cells or borne on short, almost 

 colorless branches from the terminal cells; zoosporangia terminal, 

 sessile on the vertical rows of cells, ellipsoid or ovoid. 



Growing on stones in the lower littoral and upper sublittoral belts. 

 Port Clarence, Alaska, and Iliuliuk, Unalaska. 



Areschoug, Observ. Phyc. part 3, 1875, p. 22 ; Kjellman, Om 

 Bering. Alg., 1889, p. 49; Setchell and Gardner, Alg. N.W. Amer., 

 1903, p. 253. 



The plants of Kjellman from Port Clarence are sterile and those 

 of Setchell and Lawson from Iliuliuk are not to be found for 



reexamination. 



2. Lithoderma lignicola Kjellm. 



Thallus forming thin, uneven, elongated, almost linear, somewhat 

 confluent crusts, 250/i or more thick ; the basal layer composed of 

 united, radiating branched rows of thick-walled cells, nearly parallel, 

 not flabellate ; the basal layer giving rise to vertical rows of cells, 20 

 or more, branching occasionally, loosely united above; cells 10-15/a 

 long, 8-10/* diam. ; character of reproductive organs unknown. 



Growing on piles in the littoral belt. St. Michael, Alaska?. 



Kjellman, Alg., Arc. Sea, 1883, p. 256, pi. 26, figs. 8-11 ; Setchell 

 and Gardner, Alg. N.W. Amer., 1903, p. 253. 



This species was discovered by Kjellman "in the Norwegian Polar 

 Sea." Specimens were taken at Talvik in the middle of September, 



