1920] Setchell-Gardner : Chlorophy&eae 237 



Collins (1909, pp. 209, 210) and keep them separate, at least for the 

 present, for the reasons given above. 



On the Atlantic coast of North America, Monostroma Grevillei is 

 a summer plant in the Greenland waters (Upper Boreal Zone), but 

 invades the North Temperate Zone in spring-time. On the Pacific 

 Coast, our only specimens are from Bering Sea but Collins (1903, 

 p. 13) states that it descends to Monterey, California, which is much 

 above its accustomed temperature. 



The reference of Collins to Monterey is based on two small speci- 

 mens found attached to Gloiosiphonm verticillaris Farl., collected by 

 Mrs. J. M. Weeks. Reexamination of these specimens, although not 

 convincing, leads as to the opinion that they may be nearer Mono- 

 stroma zostericola than to any forms of M. Grevillei. 



Collins gives, in addition to the typical form, the two following 

 varieties as found on our coast. Since we have access to very scanty 

 material we follow him and other authorities as to their disposition. 



Monostroma Grevillei var. lubricum (Kjellm.) Collins 



Frond up to 15 cm. long, pale or whitish green, delicate, very 

 lubricous and flaccid, of irregular outline, laciniate, plicate, margin 

 often crisped and lacerate ; frond 18-22/a thick ; cells seen superficially, 

 circular or rounded angular, often in twos or fours, cell wall thick; 

 in cross section horizontally ovate or oblong, 4.5-8/^ high. 



Floating in shapeless masses in quiet waters. Alaska. 



Collins, Green Alg. N. A., 1909, p. 209. Monostroma lulricum 

 Kjellman, Spetsb. Thall., 1877, p. 48, pi. 4, f. 8, 9; Setchell and 

 Gardner, Alg. N.W. Amer., 1903, p. 207. 



Monostroma Grevillei var. Vahlii (J. Ag.) Rosenv. 



More slender in form, often cylindrical, retaining its saccate shape 

 longer, and with cells arranged in more or less distinct longitudinal 

 series. An early spring plant. 



Alaska (Kukak Bay, Saunders, Sitka, Gardner). 



Rosenvinge, Groenl. Havalg., 1893, p. 949; Collins, Green Alg. 

 N. A., 1909, p. 209. Monostroma Vahlii J. G. Agardh, Till Alg. Syst., 

 VI, 1883, p. 109, pi. 3, f. 84-89 ; Saunders, Alg. Harriman Exp., 1901, 

 p. 410; Setchell and Gardner, Alg. N.W. Amer., 1903, p. 208. 



We have seen only a fragment collected by one of us (Gardner) 

 at Sitka. This seems, however, to be clearly the Monostroma Vahlii 

 of J. G. Agardh. 



