igo TUFTS COLLEGE STUDIES, VOL. II, No. 3 



KEY TO THE SPECIES OF STICHOCOCCUS. 



I. Cells cylindrical. 2. 



i. Cells swollen. 4. 



2. Plant of moist places, not submerged. i. 5". bacillaris. 



2. Aquatic. 3. 



3. Marine. 3. 6". marinus. 



3. Fresh water. 6. 



4. Cells usually over 5 M diam. 4. 5 1 . subtilis. 



4. Cells usually under 5 M diam. 5. 



5. Cells 3-3.5 fj- diam., i-io diam. long. 2. S. scopulinus. 



5. Cells 2.5-3 A* diam., 1-4 diam. long. 



i. S. bacillaris f. confervoideus. 



6. Plant of moist places, not submerged. 5. S.flaccidus. 



6. Fresh water plants, submerged. 7. 



7. Unbrauched ; filaments readily breaking up. 6. S.fluitans. 



7. With rhizoidal branches ; not readily breaking up. 7. S. rivularis. 



1. S. BACILLARIS Nageli, 1848, p. 77, PL IV. G., fig. i; 

 Hazen, 1902, p. 160, PI. XXII, fig. i ; P. B.-A., No. 1024. 

 Filaments pale green, 2.5-3 /" diam., cylindrical, of 2-24 cells, 

 very readily separating; cells 1-4 diam. long; chromatophore 

 elliptical, thin and pale. Fig. 69. On damp ground, rocks, and 

 on flower-pots in greenhouses. Nova Scotia, N. H., Mass., 

 N. Y., Kansas, N. C., Cal. Europe. 



Forma CONFERVOIDEUS Hazen, 1902, p. 160, PI. XXII, figs. 

 2 and 3. Submerged form ; filaments longer, not so readily 

 breaking up. Found among other algae, in rather quiet water, 

 forming crisped or floccose masses. Mass, to N. J. 



2. S. SCOPULINUS Hazen, 1902, p. 161, PI. XXII, figs. 4-6. 

 Filaments forming long, bright green, lubricous masses; cells 

 cylindrical, 3-3.5 M diam., i-io diam. long; wall very thin, 

 chromatophore pale, slender ; pyrenoid indistinct. 



Slightly larger than S. bacillaris forma confervoidea , and with 

 longer cells ; at the original locality, near New York city, the 

 only station yet recorded, it formed long skeins on dripping 

 rocks ; when collected it soon breaks up, or produces abundant 

 zoospores. 



3. S. MARINUS (Wille) Hazen, 1902, p. 161, PI. XXI, figs. 

 8 and 9; Ulothrix variabilis var. marina Wille, P. B.-A., No. 

 615. Filaments dark green ; cells cylindrical, 5-6 /A diam., cells 

 1-2 diam. long; chromatophore a roundish or oblong plate; 

 pyrenoid indistinct. Me., R. I., Conn., Cal. Northern Europe. 



The only marine species ; much more slender than any of our 



