1920] SetcheU-Gurdner : Chlorophyceae 161 



Bryopsis corticulans is a coarse, dark green species, fairly regu- 

 larly distichous and with pinnules little reduced in size from the 

 axis whence they spring. It has, in the older plants at least, small 

 clusters of short rhizoidal outgrowths at the bases of the lower (or 

 even of the upper) branches. Thus far it has been observed only in 

 winter and spring on the coast of California, but in Puget Sound it 

 seems to occur also in mid-summer. It is closely related to B. plumosa, 

 but it is coarser, with more regularly occurring corticulating rhizoids, 

 and with the pinnae more elongated lanceolate. It is still a question 

 whether we have true B. plumosa or not, and it is not absolutely 

 certain that B. corticulans differs sufficiently from it to be always 

 distinguishable. The pinnules of B. corticulans, however, are coarser, 

 more robust, and more abruptly and unequally rounded at the base 

 than those of any of the plants usually referred to B. plumosa. The 

 lower plumules are not only abruptly and extremely constricted at 

 the base, but possess bases which bulge out on the lower side where 

 the rhizoidal growths issue. Thus far the great majority of the 

 strictly distichous Bryopsis from our coast seem referable to B. corti- 

 culans rather than to B. plumosa. 



4. Bryopsis plumosa (Huds.) Ag. 



Plate 14, figs. 1, 2 



Thallus not more than 10 cm. high, deep green and shining, more 

 or less branched once or twice, seldom more, the ultimate branches 

 forming plumes with distichous, slender pinnules gradually narrowed 

 above and to a base which is slightly, if at all, rounded; bases of the 

 lower branches showing several short lobes. 



On floats, Puget Sound Marine Station, Friday Harbor, San Juan 

 Island, Washington, collected by Annie M. Hurd. 



Agardh, Sp. Alg., vol. 1, part 2, 1822, p. 448 ; Collins, Green Alg. 

 N. A., 1909, p. 403. Viva plumosa Hudson, Flora Anglica (2nd Ed.), 

 1778, p. 571. 



The type locality of Bryopsis plumosa is Exmouth in Devon on 

 the south coast of England, and no type specimen seems to be available. 

 The species is widespread, as far as report goes, but it is very doubtful 

 whether by any means all the plants, even of Europe, assigned to it, 

 really are properly referred. It is distichous, as generally defined, 

 and has broad triangular plumes. More investigation is needed to 

 determine exactl}^ the original application of the name, if possible, and 



