STICHOCOCCUS 165 
Exsıc : Phyc. Bor. Am. 776. 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.; Kütz. Spec. Alg. 349. 1849. Klebs (98), how- 
ever, has maintained the specific distinctness of the form as Hor- 
midium nitens Menegh. in spite of the fact that morphologically 
it is hardly separable from S. faccidus. 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. 
Ale Eur. 2575, collected by Wolle at Bethlehem, Pa., and Hor- 
miscia flaccida nitens, Tilden, Am. Alg. 6, from Minnesota, are 
hardly distinguishable from A. subtilis. The figure given by 
Saunders (Flora of Nebraska, ad 22. f. 2. 1894) certainly has 
nothing to do with Stichococcus ; it appears to be a form of Mou- 
geotia. 
6. SricHococcus FLUITANS Gay, Bull. Soc. Bot. France 40: 
CLXXIV. f. z. 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 p in diameter, 1-3 times as long; chromatophore large and 
opaque, obscuring somewhat the dull pyrenoid. Reproduction 
by zoospores infrequent (X. 22, f. 7-9). 
Exsic.: Phyc. Bor. Am. 759. Melrose, Mass., May 1, 1900 
(F. S. Collins). 
