TIIK \l.<;\i: OF lil'.K.MI'DA. 



L9 



1S45-49, p. 25, PI. XXXVII, fig. I; P. B.-A., No. 2054. Among 

 other algae in a coating on rock between tide marks, North Shore, 

 Sept., Collins. 



3. S. subsalsa forma oceanica Gomont, 1893, p. 274; P. B.-A., 

 No. 2053. Among other algae at various stations. 



Oscillatoria Vaucher. 



1. Filaments torulose. 

 1. Filaments not torulose. 



2. Trichomes 18-36 m diam., loosely spiral. 



2. Trichomes not spiral. 

 3. Trichomes and stratum dull red. 

 3. Trichomes and stratum not red. 



4. Limicolous; trichomes 17-29 n diam. 



4. Trichomes 6-11 /x diam. 

 5. Limicolous or saxicolous; black-olive. 

 5. Epiphytic; aeruginous, light green or light brown. 



6. Trichomes not attenuate at tip. 



6. Trichomes attenuate at tip. 

 7. Trichomes 4-10 /x diam. 

 7. Trichomes less than 3 n diam. 



8. Apical cell capitate. 



8. Apical cell not capitate. 

 9. Trichomes 3 /x diam. or more. 

 9. Trichomes less than 3 n diam. 



10. Distinctly marine. 



10. Plant of fresh water pools. 



11. 



2. 



6. 



O. Bonnemaisonii. 



3. 



2. O. miniata. 



4. 



O. margaritifera. 



5. 



: . O. nigro-viridis. 



5. O. Corallinae. 



7. 



8. 



6. O. tenuis. 



7. O. amphibia. 



8. O. amoena 



9. 



10. 



O. longearticulata. 



9. O. laetevirens. 



10. O. formosa. 



1. O. Bonnemaisonii Crouan ex Gomont, 1893, p. 235, PI. VI, 

 figs. 17-18; P. B.-A., No. 2055. Forming floating masses in ditch 

 in Pembroke Marsh, Aug., Collins. 



2. O. miniata Hauck ex Gomont, 1893, p. 236; P. B.-A., Xo. 2156. 

 Hungry Bay, April, May, Collins. Forming a deep red film on the 

 bottom, also floating clots adhering to everything. The filaments are 

 usually about 20 /jl diam., but occasionally as high as 45 m- The plant 

 decays very quickly, and even when put on paper with a promptness 

 ample for most Oscillatorias, the coloring matter stains the paper pur- 

 ple, and the filaments remain nearly colorless. 



M. O. margaritifera Kiitzing ex Gomont, 1893, p. 236, PL VI, 

 fig. 19. In brackish pool with other algae, April, Sept., Collins. 



4. O. nigro-viridis Thwaites ex Gomont, L893, p. 237, PI. VI, 

 fig. 20. On rocks wet by salt water, Jan., Fallow. 



