162 Ulothricaceae 



18 May, 1901 (570B). Mt. Desert, Maine, July 17, 1900 (F. S. 

 Collins). 



The figure accompanying Professor Wille's original description 

 of this form leads us to doubt whether our American specimens 

 should be identified with it. There is no question, however, that 

 both of the Connecticut specimens are the same species and also 

 no question, in our judgment, that they should be referred 

 to Stichococcus rather than to Ulothrix. 



Professor Wille's identification of the specimen issued in the 

 Phycotheca was not based, of course, upon living material, a con- 

 dition which is essential to a critical treatment of such fine species. 

 Under the kind direction of Mr. Holden, we made a careful 

 attempt to duplicate the specimen from the same station, but in 

 vain. In a tidal creek of the same harbor, however, where the 

 conditions were exactly similar, we obtained material which was 

 undoubtedly of the same species as that collected by Mr. 

 Holden. 



From a careful study of this fresh material in comparison with 

 exsiccatae, the species proves to be more closely allied to Sticho- 

 coccus subtilis than to Ulothrix variabilis. The cells are frequently 

 longer than in the latter species, the chromatophore is more like 

 that of 5. subtilis and lacks the clearly refractive pyrenoid charac- 

 teristic of Ulothrix. The appearance of the chlorophyll was 

 decidedly different from that of U. implexa with which this species 

 was associated, and showed the bluer tint which is more character- 

 istic of many Stichococcus species. The fact that only one zoospore 

 was formed in a cell, while not conclusive proof, points to Stichococcus 

 rather than Ulothrix, for filaments of U. implexa possessing only a 

 slightly larger diameter contained several zoospores in a cell. On 

 the whole, therefore, we are convinced that the species belongs in 

 Stichococcus. 



4. Stichococcus subtilis (Kiitz.) Klercker, Flora, 82 : 103. 1896 

 Ulothrix subtilis Kiitz. Phyc. Germ. 197. 1845 ; Spec. Alg. 

 345. 1849 5 Tab. Phyc. 2 : //. 85./. 1. 1852. Rabenh. Flor. Eur. 

 Alg. 3 : 365. 1868. Kirchn. Krypt. Flor. Schles. 2 1 : 77. p. p. 

 1878. Wille, F. W. Alg. 135. pi. 118. f. p, 10 p. p. 1887. 

 Chodat, Beitr. Krypt. Flor. Schweiz, I 3 : 268. 1902. 



