448 University of California Publications in Botany [^'^ol. 6 



increase in size; gonidia angular, 1.8-2.4;a diam., formed by simul- 

 taneous division of the contents. 



Growing on Iridaea minor, in the lower littoral belt. Carmel, 

 Monterey County, California. 



Only a single antheridial plant of Iridaea has been observed with 

 this epiphyte growing upon it, but doubtless it is common and prob- 

 ably grows on other sexes of the same species. Iridaea nvinor is usually 

 rather dark colored which makes the presence of Radaisia somewhat 

 obscure and this condition may account for its not having been 

 previously observed. 



The gonidangia of R. epiphytic'a depart somewhat from the typical 

 form of the genus. Since the erect filaments are complex in each 

 sheath resulting from vertical as well as horizontal divisions, often 

 irregular and oblique, the gonidangia are also complex consisting of 

 a group of transformed terminal cells instead of a single terminal cell 

 as is usually- the case. The original cell wall or sheath persists as 

 the erect filaments elongate and become complex. Likewise when the 

 terminal cells metamorphose into gonidangia the original sheath of 

 a group of cells persists, and a compound gonidangium is the result. 



In conclusion I wish to acknowledge a debt of gratitude which 

 I owe to Professor W. A. Setchell who collaborates with me in pre- 

 senting the new species of algae of this paper, and who has kindly 

 prepared the Latin diagnoses. 



EMENDATION 



Since publishing New Pacific coast marine algae I, June, 1917, 

 Professor Farlow has called our attention to the publication of Sar- 

 gassum Palmeri Grunow (Verb, zool.-bot. Ges., Vienna, 1915, vol. 65, 

 p. 338) based upon the plant distributed in Farlow, Anderson and 

 Eaton, Algae Exsiccatae Amer.-Bor., no. 102. This plant was referred 

 by Setchell and Gardner to S. disseciifolium (Gardner, loc. cit., 

 p. 386). The type of S. dissectifolium, however, is a plant collected 

 at Santa Catalina Island, southern California, and deposited in the 

 Herbarium of the Universitj' of California as no. 99,540. The copy 

 of the above publication, 1915, has not as yet reached the Universitj' 

 of California, presumably on account of the war. 



