172 University of California Puhli cat ions in Botany [Vol.8 



in the vicinity of the Pnget Sound Marine Station, and came to the 

 conclusion tliat they exhibited all the possible variations assigned to 

 the varieties navae-zelandiae and californicum, bntli of which have 

 been accredited to our coast. Cotton (1912, p. 114-119, pi. 7, 8, f. 8-5) 

 has discussed the species as found on tlie coasts of Ireland and of 

 Scotland with remarks on the varieties described by himself and 

 J. G. Ag-ardh. 



As usually found, Codiiim fragile gives no impression of being 

 tomentose, but occasionalh' plants are found which are covered with 

 a thick coating of hairs. Miss Hurd (1916m, p. 111—116) has dis- 

 cussed the hairs on the utricles of this species in some detail, but 

 did not find the extreme tomentose condition found by one of us 

 (Gardner) at Redondo, California where the hairs were 2 mm. long, 

 and so denselj^ covering the whole plant as to make it seem as if para- 

 sitized. It seems that the conditions causing such extreme growth of 

 hairs have not as yet been definitely ascertained (cf. Hurd, loc. cit., 

 and Oltmanns, 1905, p. 239). There is still a fertile field for obser- 

 vation and experimentation in this subject. 



Codium fragile seems to be a widespread species. J. G. Agardh 

 described it as occurring on the Avest coast of North America, in New 

 Zealand, in Australia and in Tasmania. It has been found also in 

 the Cape of Good Hope region and in the region of the Straits of 

 Magellan (Hariot, 1889, p. 33, and Svedelius, 1900, p. 299) and on 

 the coasts of Scotland and of Ireland (cf. Cotton, 1912, p. 115). 

 This is certainly a wide distribution in widely separated waters, but 

 at least the waters have approximately the same temperatures for 

 certain portions of the year. It is interesting to compare in this con- 

 nection Codium divaricatum f. hyhrida Okamura (1915, p. 157, pi. 

 135, f. 17), which is suggested as being a hybrid between C. divari- 

 catum Holmes and C. fragile (Suring.) Hariot. 



4. Codium decorticatum (Woodw.) Howe 



Thallus sparingly branched, diehotomous, up to 5 dm. or more 

 long, usually decidedly flattened under the dichotomies; peripheral 

 utricles obovoid to broadly clavate, thin walled throughout, obtuse, 

 135-520yu, maximum diameter, 500-700jli long. 



La Paz, Lower California. 



Howe, Phyc. Studies V, 1911, p. 494. Ulva deoorticaia Woodward, 

 Observations upon the generic characters of TJlva, 1797, p. 55. 



