Myxophyceae 87 



II Turns of the spiral dose together. 



1 Trichomes 1.2-1.8 mic. in diameter, forming a dense regular spiral 



3-4.5 mic. in diameter, the turns being contiguous 



S. versicolor 



2 Trichomes 1-2 mic. in diameter, forming a somewhat irregular dense 



or rarely regular spiral 3-5 mic. in diameter, the turns being con- 

 tiguous or nearly so S. subsalsa 



III Trichomes forming slender, flat, continuous bands (when untwisted 



forming a complete ring), normally flattened and twisted, with 

 one to four or more turns. S. duplex 



175. Spirulina meneghiniana Zanardini. Notozie intorno alle Cellulari ma- 

 rine delle Lagune e de littorale di Venezia. Atti del I. R. Istituto 

 veneto. 6: 80. 1847. Gomont. Monogr. Oscill. 270. pi. 7. f. 28. 1893. 

 De Toni. Syll. Algar. 5: 209. 1907. 

 Collins. Notes on New England Marine Algae. — VI. Bull. Torr. Bot. 

 Club. 23. 1 : 1896; Preliminary 'Lists of New England Plants. — V. Marine 

 Algae. Rhodora. 2: 43. 1900; Notes on Algae. — IV. Rhodora. 3: 289. 1901. 

 Collins, Holden and Setchell. Phyc. Bor.-Am. Fasc. 18. no. 852. 1901. 



Plate IV. fig. 45. 

 Plant mass compact, blue-green; trichomes i. 2-1.8 mic. in diameter, 

 flexuous, curved, twisted into a more or less loose, somewhat irregular 

 spiral, 3.2-5 mic. in diameter, the distance between the turns being 3-5 mic; 

 cell contents pale blue-green. 



Massachusetts. In scattered filaments among other algae in a ditch of 

 brackish water, salt marshes. Revere. August 1893; in considerable quantity 

 in rock tide pools above high water mark, but reached by spray in stormy 

 weather, on the Marblehead shore, near Clifton Station. July 1901. (Col- 

 lins). 



176. Spirulina major Kuetzing. Phyc. Gen. 183. 1843. Gomont. Monogr.^ 

 Oscill. 271. pi. 7. f. 29. 1893. De Toni. Syll. Algar. 5: 210. 1907. 



Tilden. American Algae. Cent. I. no. 79. 1894. (S. subsalsa Oersted) ; 

 List of fresh-water Algae collected in Minnesota during 1894. Minn. Bot. 

 Studies, i: 236. 1895; American Algae. Cent. II. no. 193. 1896; Observations, 

 on some West American Thermal Algae. Bot. Gaz. 25: 103. 1898. Collins, 

 Holden and Setchell. Phyc. Bor.-Am. Fasc. 11. no. 501. i8g8. Setchell. 

 Notes on Cyanophyceae. — III. Erythea. 7: 54. 1899. Bessey, Pound and 

 Clements. Additions to the Reported Flora of the State. Bot. Surv. Nebras- 

 ka. 5: 14. 1901. Collins, Holden and Setchell. Phyc. Bor.-Am. Fasc. 23. 

 no. 1 102. 1903. Setchell and Gardner. Algae of Northwestern America. 

 Univ. Calif. Pub. Bot. i: 182. 1903. Buchanan. Notes on the Algae of 

 Iowa. Proc. Iowa Acad. Sci. 14: 15. 1908. 



Plate IV. fig. 46. 



Plant mass dark blue-green; trichomes 1.2-1.7 mic. in diameter, usually 

 scattered among other algae, more or less flexuous, twisted into a some- 

 what loose, regular spiral 2.5-4 mic. in diameter, the distance between the 

 turns being 2.7-S ™ic. 



