56 University of California Publications in Botany [Vol. 8 



The genus Spirulina was fouudod by Turpin in 1827 {loc. cit.) 

 with the type species named Spirulina oscillarioidcs, a name placed 

 among tlie "Species inquirendae" by Gomont (1893, p. 275, Repr.). 

 Judging from his figures {loc. cit. Planches, 2«. partie, regne organise, 

 "oscillariees," figs. 3, 3a., 36, 3c) Turpin 's plant was a mixture of 

 fresli water species of Spirulina, although some of his figures resemble 

 species of Spirogyra, but without cross walls. This appearance is 

 doubtless due to the idea of Turpin that the spiral trichome is enclosed 

 in a tube or thread of mucilage. 



Gomont (1893, p. 269, Repr.) has adopted the name Spirulina of 

 Turpin (1827) instead of the earlier Spirogyra of Link (1809, p. 20) 

 which seems to have been founded on a species of Spirulina Turpin. 

 giving his reasons in full. Since Gomont 's Monographie des Oscil- 

 lariees has been made the starting point for the nomenclature of 

 "Nostocaceae homocysteae" by the Brussels Congress (cf. Actes de 

 Illme. Congres Intern, de Botanique, Bruxelles, 1910, vol. 1, p. 103), 

 and since also the Spirogyra of Link 1820 has been placed by action 

 of the same body {loc. cit., p. 109) among the "nomina conservanda" 

 as against the " Conjugaia" of Vaucher 1803, it seems necessary as 

 well as desirable to follow Gomont. 



Key to the Species. 



1. Spiral regular, loosely coiled 1. S. major (p 56) 



1. Spiral regular, tightly coiled 2. S. subsalsa (p 57) 



L Spirulina major Kuetz. 



Plate 1, fig. 5 



Plants in mass bright blue-green, trichomes pale blue-green, more 

 or less flexuous, 1.2-1. 7/x diam., twisted into a fairly loose, regular 

 spiral, 2.5-4/A diam., with a distance of 2.7-5/x between the turns. 



Growing in brackish water. Puget Sound, Washington, to central 

 California. 



Kuetzing, Phyc. Gen., 1843, p. 183 ; Gomont, Monogr. des Oscill., 

 1892, p. 271, pi. 7, fig. 29 (1893, p. 271, Repr.) ; Setchell and Gardner, 

 Alg. N.W. Amer., 1903, p. 182. 



The species of Spirulina are to be distinguished from one another 

 by four different criteria : (1) by the varying diameter of the trichome ; 

 (2) by the horizontal amplitude of the spiral; (3) by the distance of 

 the turns of the spiral from one another, i.e., by the looseness or tight- 



