1920] Setchell-Gardner: Chlorophyceae 243 



Collins, Ulvaceae of N. A., 1903, p. 12, Green Alg. N. A., 1909, 

 p. 213 ; Setchell and Gardner, Alg. N.W. Anier., 1903, p. 209 ; Collins, 

 Holden and Setchell, Phyc. Bor.-Amer. (Exsicc.), no. 911. Mono- 

 stroma splendens Wittrock, Monostr., 1866, p. 50, pi. 3, f. 12; Setchell, 

 Alg. Prib., 1899, p. 591. Viva splcndeus Ruprecht, Tange Och., 1851, 

 p. 410. 



Monostroma fuscum var. Blyttii (Aresch.) Collins 



Frond deep green, blackish in drying, 60-70/a thick; cells "palisade- 

 form" in cross section. 



Growing in tide pools and on pebbles in tlie sublittoral belt. Van- 

 couver Island and Washington. 



Collins, Ulvaceae of N. A., 1903, p. 12, Green Alg. N. A., 1909, 

 ]^. 213. Monostroma Blyttii Wittrock, Monostr., 1866, p. 49, pi. 3, 

 f. 11. Ulva Blyttii Aresch., in Fries, Sum. Veg. Scand., 1846, p. 129. 



We are puzzled, when it comes to the discussion of Monostroma 

 fuscum, whether to treat of it as a species or as a group of species. 

 The typical Monostroma fuscum is comparatively thin (20-25jli accord- 

 ing to Wittrock, 1866, p. 53), turning only a light brown on drying 

 instead of black, and with cells quadrate or only slightly vertically 

 elongated in cross section. The var. splendens is a thicker plant (49- 

 53/A according to Wittrock, 1866, p. 51), turning black, adhering even 

 less well to paper than the typical form and with cells vertically much 

 elongated in cross section. The var. Blyttii differs from var. splendens 

 chiefly in being thicker (65-72/a according to Wittrock, 1866, p. 49), 

 but is otherwise essentially the same. 



Rosenvinge (1893, p. 940, 1894, p. 146), relying upon the obser- 

 vations of Kleen (1874, p. 42), reduces the three species of Wittrock 

 to two varieties of one, viz., var. typica and var. splendens of Mono- 

 stroma fuscum. The arrangement of Rosenvinge has been generally 

 followed and we feel that we can not do better than adopt the general 

 opinion. We have, however, followed Collins (1909, p. 213) in retain- 

 ing the varieties (or forms?) of spleiidens and Blyttii as well as the 

 typical form. The typical form is perhaps a younger or less developed 

 form and seems more distinct from both var. spleiidens and var. 

 Blyttii, than they do from one another. We may expect any, or all, 

 of the three forms anywhere along the coast from the Bering Sea to 

 the Puget Sound region. 



We have had no opportunity of observing the earlier stages of 

 growth of any of the forms of this species, but Postels and Ruprecht 



