152 University of California PuUications in Botany [Vol. 8 



p. 517) comes to the conclusion that two species, or groups of species, 

 stand out with fair distinctness, viz., Codiolum gregarium A. Braun, 

 in which species (or group) the clava is definitely constricted at the 

 line of union with the stipe, and C. pusillum (Lyng.) Kjellman, where 

 the stipe passes insensibly into the clava. Our specimens are to be 

 arranged with C. gregarium A. Braun and while their dimensions 

 differ from those given by various authors for this species, yet it 

 seems best not to attempt any separation at present. Our specimens 

 vary in length of clava from 160/^ to 240/^, and in width from 32/x to 

 64/x, while the stipe varies from 250ja to 550ja in length and from 16/a 

 to 28[x in diameter. 



2. Codiohim Petrocelidis Knckuck 



Clava ovoid or obovoid, 65-90iLi long, 20-30/x wide ; stipe relatively 

 short or sometimes absent, often tapering abruptly below into a sharp 



point. 



Growing within the thallus of Petrocelis franciscana, central Cali- 

 fornia, and of P. Middendorffii, Whidbey Island, Washington. 



Kuckuck, Bemerk. zur mar. Algenveg. Wiss. Meeres., vol. 1, 1894, 

 p. 259, f. 27 ; Collins, Green Alg. N. A., 1909, p. 152 ; Collins, Holden 

 and Setchell, Phyc. Bor.-Amer. (Exsicc), no. 2281. Chlorochytrium 

 Schmitzii Setchell and Gardner, Alg. N. W. Amer., 1903, p. 206 (in 



part) . 



Codiolum Petrocelidis was described by Kuckuck from specimens 

 growing in Petrocelis Hennedyi at Helgoland, where it had first been 

 detected many years previously by Ferdinand Cohn. It has also been 

 described as growing in Petrocelis on the coast of New England. Two 

 specimens of Codiolum growing in species of Petrocelis have been 

 collected on the Pacific Coast of North America, one in P. Midden- 

 dor ffii on the west coast of Whidbey Island, Washington, and the other 

 in P. franciscana on the coast of central California at Fort Point, 

 San Francisco. Tliese two sets of plants differ somewhat from one 

 another and also both differ in dimensions from C. Petrocelidis as 

 described by Kuckuck. Kuckuck gives (as in description above) 65/a 

 to 90/x long and 20ju, to 30/* wide as the dimensions of his type. The 

 Washington plant varies from 136/x to 180/t long and from 20/a to 44/t 

 wide for the clava, while the Californian plant shows clavae from 

 BOft to 140/t long and 28/x to 42/* wide. It seems best, however, to refer 

 them both to Codiolum Petrocelidis Kuckuck, at least for the present. 



