152 University of California Puhlications in Botany [Vol.8 



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

 stand out with fair distinctness, viz., Codiolum greyariiDn A. Rraun, 

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

 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 witli C. gregarium A. Braun and while their dimensions 

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

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

 vary in hnigth of clava from 160ju, to 240/a, and in width from 32/a to 

 64ju,, while the stipe varies from 250ju, to 55()/i, in length and from IG^a 

 to 28/x, in diameter. 



2. Codiolum Petrocelidis Kuckuck 



Clava ovoid or obovoid, 65-90/x long, 20-30/i, 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- 

 dorffii on the west coast of Whidbey Island, Washington, and the other 

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

 San Francisco. These 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) 65ju, 

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

 Washington plant varies from 136f(, to 180/x long and from 20/* to 44/i, 

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

 80/x to 140/1, long and 28/x, to 42/i wide. It seems best, however, to refer 

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



