I. 



S. 



bacillaris. 



2. 



s. 



scopulinus. 



3- 



s. 



marinus. 



4- 



s. 



subtilis. 



160 Ulothricaceae 



Synopsis of Species 



Cells cylindrical, hardly constricted at the dissepiments. 



Cell diameter 2.5-3//, I- 4 times as long, filaments short. 



Cell diameter 3-3.5 //, 1-10 times as long, filaments elongated. 



Cell diameter 5-6 /u, 1-2 times as long ; marine form. 



Cell diameter 5-6.5 [i, I -3 times as long, filaments elongated. 

 Cells constricted at the dissepiments, or somewhat tumid. 



Cell diameter 6-9.5 /*> on damp rocks, earth, etc. 5. S. flaccidus. 



Cell diameter 6.5-9^, in cascades. 6. S.jhdtans. 



Cell diameter 8-1 1 ju, forming holdfasts. 7. S. rivularis. 



i. Stichococcus bacillaris Nageli, Neue Denkschr. Allgem. 



Schweiz. Gesell. io 7 : yj.pl. 4. G. f. 1. 1849. Rabenh. Flor. 



Eur. Alg. 3: 47. /. 21. 1868. Hansg. Prod. Alg. Bohm. 



1: 139, /. 85. 1886 ; Phyc. u. Alg. Stud. //. 4. f. 5. 1887. 



DeToni & Levi, Notarisia, 2: 281-283. 1887; Flor. Alg. 



Ven. 3: 125. 1888. DeToni, Syll. Alg. 1: 6S7. 1889. 



Gay, Rech. Sur Alg. Vert. 78. pi. 11. f. ioy. 1891. 



Klercker, Flora, 82 : 102. //. 6. f. p-ij. 1896. 



Protococcus bacillaris Nag.; Kiitz. Spec. Alg. 198. 1849. 



Hormococcus flaccidus bacillaris Chodat, Beitr. Krypt. Flor. 

 Schweiz, I 3 : 269. 1902. 



Filaments pale green, fine and short (composed of 2-24 cells, 

 DeToni), very readily breaking apart ; cells cylindrical but 

 slightly constricted at the ends, 2.5-3 I 1 m diameter, 1-4 times as 

 long ; chromatophore thin and pale, elliptical [pi. 22./. 1). 



On damp earth or rock, and on flower pots, etc., in green- 

 houses, Central Park, New York, June (637). 



lb. S. bacillaris Nag. forma confervoidea f. nov. 



Filaments longer, often crisped, usually growing in association 

 with masses of Tribonema and other confervae ; cell characters as 

 in the typical form [pi. 22./. 2, j). 



Filaments scattered or in small floccose masses, in pools or 

 gently flowing water. 



Massachusetts: Pine Banks Park, Melrose, April (550). 



New York: Botanical Garden, April (534B); Central Park, 

 May. 



New Jersey : Ridgefield, April (298). 



So far as can be seen this form differs from the type only in 

 the length of the filaments and in its habitat. Neither this nor the 

 typical form has been studied sufficiently to make it possible abso- 



