170 University of Calif ornixi Puhlicatioiis in Botany [Vol.8 



150-250/i, up to 400/x diain. ; 2-4 inin. long, end wall slightly thickened 

 and witli a small depression in the center; gainetangia unknown. 



(j rowing on rocks in the lower littoral and upper sublittoral belts. 

 Extending from Kadiak Island, Alaska, to the west coast of Vancouver 

 Island, British Columbia. 



Setehell and Gardner, Alg. N.W. Amer., 1903, p. 2:31, pi. 17, f. 

 8-11. Codium adhaerens Tilden, Amer. Alg. (Exsicc), no. 370 (not 

 of Agardh). 



The type specimen is a small plant about three centimeters in 

 diameter, or possibly it may be a small lobe of an old thallus that 

 liad become, loosened at the base and by wave action had been torn 

 from the remainder of the thallus. Since the publication of the species, 

 excellent material, several inches across, has come from Alaska to 

 the Herbarium of the University of California through the courtesy 

 of T. C. Frye and G. B. Rigg. These show that the species is con- 

 siderabl}' expanded and variously lobed, though not adhering so firmly 

 and closely to the rock as do other incrusting form^ of this genus. 

 The utricles in the upper portion away from the margin are relatively 

 much longer and narrower than those figured for the type (Setehell 

 and Gardner, loc. cit.). 



New utricles arise from the older one b}^ lateral branching, as 

 many as four and five appearing at a time. The point of origin 

 remains constricted, and a plug cuts off the new utricular protoplast 

 from the old one. In due course these branches may drop off, the 

 old utricle continuing to grow, and later giving rise to others. From 

 their bases the new utricles give rise to several rhizoidal filaments. 

 The species probably fruits in the winter, since all the material thus 

 far collected is sterile, and the collections have all been made in the 

 summer. 



Setehell and Gardner (loc. cit., p. 232) suggested that possibly the 

 plant distributed by K. Okamura (Algae Japonicae Exsiccatae, no. 

 49) under C. mamillosum belongs under C. Rittcri. Okamura (1915, 

 p. 152) dissents from this suggestion. Since having had opportunity 

 for further study of C. Ritteri, reexamination of the Japanese plant 

 leads us to conclude with Okamura that his plant is not the same as 

 C. Ritteri, but we do not agree with him that it is the same as C. 

 mamillosum of Agardh. 



We have not seen the specimen of Codium mamillosum of Coville 

 and Rose (1898, p. 353) from Preobrazhenskoye, Copper Island, in 

 the Commander Group, Siberia, but, on account of the low tempera- 



