542 TJniversity of California Piiblicaiions in Botany [Vol. 8 



5. Colpomenia sinuosa f . deformans S. and G. 



Fronds rigid, erect, membranaceous, cavernous, lower part tuber- 

 culate in the juvenile state, later developing one or more irregularly 

 cylindrical, sack-like, at times flattened, projections from the upper 

 surface, 1-7 cm. high, surface of frond smooth, somewhat lacerated 

 when aged ; color dark brown. 



Attached to rocks and to other algae by a broad sessile base, in the 

 lower littoral belt. Ranging from Cook Inlet, Alaska, to the Gulf of 

 California. 



Setchell and Gardner, Alg. N.W. Amer., 1903, p. 242, pi. 18, figs. 

 13-15 ; Mar. Alg. Gulf of Calif., 1924, p. 726, pi. 19, figs. 61, 62. Scyto- 

 siplion huUosus Saunders, Phyc. Mem., 1898, p. 163, pi. 31, figs. 1-7, 

 Alg. Harriman Exp., 1901, p. 421; Tilden, Amer, Alg. (Exsicc), no. 

 351. 



The Scytosiphon huUosus Saunders always arises from a sinuous, 

 lobed base which may be so small as to seem almost like a disk, but 

 varies to a Colpomenia sinuosa type of considerable size. We have 

 already discussed this elsewhere (1903, p. 243, pi. 18, figs. 13-15). 

 When the long finger-like lobes are reduced to one and the surface is 

 smooth, it is the typical form of Saunders, but more often the long 

 lobes are several and unequal and, at times, all are short. It seems 

 that certain areas grow more rapidly and this differentiation completes 

 the series from the forms of var. typica to the extremes of var. 

 deformans. 



27. Hydroclathrus Bory. 



Fronds spherical or irregularly ovate, hollow, similar to those of 

 Colpomenia, entire when young, at first becoming fenestrate, but 

 broken later into a well formed lattice work, the meshes being variable 

 in shape and size ; reproduction by plurilocular gametangia scattered 

 over the whole outer surface of the frond ; hairs growing in groups in 

 shallow depressions over the outer surface of the frond. 



Bory, in Diet, class., vol. 8, 1825, p. 419. 



The type and only known species of the genus is Hydroclathrus 

 clathratus. The completeness of the perforation of the thallus of the 

 single species of the genus Hydroclathrus readily separates it from the 

 various forms of Colpomenia, although odd plants of C. sinuosa var. 

 tuherculata often become considerably, but not regularly, perforated 

 through spotwise localization of groM^th. The origin of the holes has 



