16 rnivcrsiiij of California Publications in Boiany [Vol.8 



us, nor does it seem possible that the colonies described by Wille could 

 have been built up by such restricted direction of cell division. Plowe 

 (1914, p. 14), who has made the most careful study of the species of 

 this grenus, says of his C. epiphytica, "cell divisions apparently occur 

 in various planes." 



Key to the Species 



1. Colonies strictly superficial 2 



1. Colonies penetratinc; into substratum 3. C. lutea (p 18) 



2. Cells 1 — 1.5/A X 2/A, arranged in vertical rows 1. C. tuberculosa (p 16) 



2. Cells 0.8/A X 1.2/M, cells not in vertical rows, except possibly in very early 

 stages 2. C. conferta (p 17) 



1. Chlorogloea tuberculosa (Hansg.) Wille? 



Cells in young colonies arranged in rows from the substratum out- 

 ward, 2/i, long, 1-1. 5/A diam., yellowish green. 



Epiphytic on Cladophora. Bairds Point, Straits of Juan de Fuca, 

 British Columbia. 



Wille, Algolog. Not. I-VI, 1900, pp. 2-5, pi. 1, figs. 1-6 ; Setchell 

 and Gardner, Alg. N.W. Amer., 1903, p. 182. Pringsheimia scutata 

 f. cladophorac Tilden, Amer. Alg. (Exsicc), no. 382 (in part?). 

 Palmella ? tuberculosa Hansg., Neue Beitr. zur Kenntniss der Meeres- 

 algen, 1892, p. 240, pi. 6, fig. 9. 



It is extremely doubtful whether Chlorogloea tuberculosa should 

 be retained as a member of the algal flora of the Pacific coast of North 

 America. In an earlier paper (cf. Setchell and Gardner, 1903, p. 182) 

 we referred here with some doubt a plant distributed under the name 

 of ''Pringsheimia scutata f. cladophorac" hy Tilden (Amer. Alg., 

 no. 382). It was our impression at that time that there was to be 

 found in the specimen examined a small celled plant occurring in 

 tubercular masses, in which the cells were arranged in more or less 

 distinct vertical rows. We also noticed certain large rounded cells 

 which we suggested might be young gonidangia. More recently M. A. 

 Howe (1914, p. 12) has studied another of the Tilden specimens and 

 has failed to find any trace of a Chlorogloea present but a unistratose 

 layer of smaller cells intermingled with larger cells. Howe suggests 

 that the Tilden name "was intended to apply to some species of 

 Dermocarpa." We, also, have made further studies of the Tilden 

 plant and have found several seemingly distinct things, not all of 

 them identifiable. The principal plant is what we have named and 

 described as Xenococcus Cladophorae (cf. Gardner, 1918o,, p. 461, 



