Stichococcus 165 



Exsic: Phyc. Bor. Am. 116. Cambridge, Mass., Jan., 1890 

 (W. C. Sturgis). 



On wet rocks and on moist bark of trees. Probably widely 

 distributed. 



Massachusetts: Reading, Aug. 28, 1898 (F. S. Collins). 



New York: Central Park, April to June (315, 536, 618); 

 Greenhouse, Botanical Garden, June. 



This form at times resembles .S. subtilis, but is generally distin- 

 guishable from that species by its shorter, tumid cells with the 

 thicker cell-wall ; it is also less aquatic in its tendencies. 



We have been unable to find this species on trees, but Mr. 

 Collin's specimen shows a luxuriant growth on willow bark. 



Most recent writers have included in the synonymy of this 

 species, or at most have considered as a variety of it, Ulothrix 

 nitens Menegh.; Kiitz. Spec. Alg. 349. 1849. Klebs ('98), how- 

 ever, has maintained the specific distinctness of the form as Hor- 

 midiiun nitens Menegh. in spite of the fact that morphologically 

 it is hardly separable from 5. flaccidus. We have seen no living 

 specimens that could be referred to this form, and cannot, there- 

 fore, express an opinion of any weight regarding the characters, 

 chiefly physiological, upon which Klebs grounds its specific dis- 

 tinctness. 



The American exsiccatae, Ulothrix (Hormidium) nitens Rabenh. 

 Alg. Eur. 2515, collected by Wolle at Bethlehem, Pa., and Hor- 

 miscia flaccida nitens, Tilden, Am. Alg. 6, from Minnesota, are 

 hardly distinguishable from £. snbtilis. The figure given by 

 Saunders (Flora of Nebraska, //. 22. f. 2. 1894) certainly has 

 nothing to do with Stichococcus ; it appears to be a form of Mou- 

 geotia. 



6. Stichococcus fluitans Gay, Bull. Soc. Bot. France 40 : 

 CLXXIV./. 7. 1893. Klercker, Flora, 82 : 103. 1896. 



Filaments yellowish-green, often much crisped and densely 

 interwoven, torulose, sometimes geniculate, very readily breaking 

 up into single cells ; cells slightly constricted at the dissepiments, 

 6.5-9/i in diameter, 1-3 times as long; chromatophore large and 

 opaque, obscuring somewhat the dull pyrenoid. Reproduction 

 by zoospores infrequent [pi. 22, f. 7-9). 



Exsic: Phyc. Bor. Am. 739. Melrose, Mass., May 1, 1900 

 (F. S. Collins). 



