THE GREEN ALGAE OF NORTH AMERICA 17 



58. S. HYDRODICTYA Transeau, 1915, p. 28. Cells 75-100 X 

 210-360/4; dissepiments plane; chromatophores 7-10, either 

 straight or spiral, and making one-tenth to one-half turn ; fer- 

 tile cells more or less inflated ; tube formed by the male cell ; 

 spores lenticular or globose-lenticular, 80-120 X 110-195 /"* 

 brown, membrane pitted. 111. 



59. S. RETICULATA Nordstedt in Wittrock & Nordstedt, 

 Alg. Exsicc., No- 362; De Toni, 1889, p. 774. Filaments 

 28-40- fj. diani., cells 4-11 diam. long; dissepiments usually 

 replicate ; chromatophores 1-3, usually 2, making about 4 

 turns ; fertile cells somewhat swollen at the middle ; spores 

 ovate-ellipsoid, 46-56 X 80-108 //., yellow, membrane irregularly 

 reticulate. Mass., Fla. Brazil. 



60. S. AREO^ATA L,agerheim, 1883, p. 56, PI. I, figs. 18-20. 

 Filaments about 36 ^ diam. ; cells 5-9 diam. long ; dissepiments 

 replicate; chromatophores 1-2, making 4-9 turns; fertile cells 

 swollen; spores ovoid or rarely globose, 45-57 X 60-120 //,, 

 brownish yellow ; membrane densely areolate. Me. Europe. 



61. S. FALLAX (Hansg.) Wille, 1900, p. 16, Pi. I, figs. 19- 

 26; Transeau, 1915, p. 30; 6". insignis var. fallax Hansgirg, 

 i888a, p. 253 ; . inconstant Collins, 1912, p. 73 ; P. B.-A., Nos. 

 1768, 1570, 1571. Cells 33-45 p- diam., 2-8 diam. long ; dissepi- 

 ments partly replicate, partly plane ; chromatophores 3-4, 

 slender, with many pyrenoids, straight or slightly spiral ; con- 

 jugating tube formed by male cell ; female cell much swollen ; 

 spores ellipsoid, 45-80 X 75- 140 /A, brown, membrane with net- 

 work of fine raised lines. Mass., 111. Europe. 



Transeau's disposition under this species of forms attributed 

 to three other species is followed here, as the best in our pres- 

 ent state of knowledge of them. It is quite likely that there 

 may be changes when more is known. As noted by Transeau, 

 1915, p. 24, it is doubtful if 6". luteliana occurs in America ; all 

 references so far appear to refer to the present species. G. A. 

 Hill, I9i6a, p. 247 has a note on 5 1 . lutetiana, apparently made 

 from sterile material, and based on the description in Collins, 

 1 99, P- IJ 4- While the identification is doubtful, the observa- 

 tions on the chromatophores are interesting, indicating that in 

 Spirogyra species with normally one spiral this may grow 

 rapidly, turn back from the dissepiment and continue growing, 

 afterwards breaking apart, when the appearance is quite that 

 of two normal and distinct chromatophores. 



