CAROTINOIDS IN THE CRYPTOGAMS 111 



The algae frequently live in symbiosis with fungi or other plants. 

 Their characteristic color gives them their common name, the blue- 

 grcen alga-. They are among the lowest forms of plant life which 

 are known. 



The piunients of the blue-green algae have attracted the attention 

 of a number of investigators beginning with Nageli (1849) who ex- 

 pressed the belief that these organisms contain a special pigment, 

 which he called phycochrome, present in two modifications, a blue- 

 green phycocyan, and an orange phycoxanthin. It was thus that the 

 latter name, later applied to the pigment of the Phaeophycew, had 

 its origin. The various species of blue-green algie which have been 

 examined for carotinoid pigments are given in Table 11. 



TABLE 11. MYXOPHYCEAE FOUND TO CONTAIN CAROTINOIDS 



Order Rirulariqcece (highest forms). 



CalotJirix species Kraus and Millardet, 1868. 



Rivularia species Kohl, 1902. 

 Order Scytonemaccce. 



Tolypothrix species Kohl, 1902. 

 Order Noslocacea. 



Nostoc species Kraus and Millardet, 1868; van Wisselingh, 1915. 



Nodularia van Wisselingh, 1915. 



Anabacna flos aquce Bub. Tammes, 1900; van Wisselingh, 1915. 

 Order Oscillatoriacece. 



OscillatoriaSorby, 1873; Reinke, 1876; Monteverde, 1893. 



Oscillntoria (Oscillaria) limosa Kraus and Millardet, 1868; Kraus, 1872. 



Oxcillaloria laptotricha Molisch, 1896. 



Oscillatoria Frorlichii Tammes, 1900; Kohl, 1902. 



Phormidium ywZpare Nebelung, 1878; Kohl, 1902. 

 Order Chroococcacece (lowest forms). 



Microcystis (Polycystis) flos aquce Wittr. (fresh water) Zopf, 1900. 



A survey of the observations of the various investigators shows 

 conclusively that carotinoids are normal constituents of the Myxo- 

 phyceae. This lias been demonstrated microchemically by Molisch 

 (1896), Tammes (1900), Kohl (1902) and van Wisselingh (1915). 

 Spectroscopic studies were made by Reinke (1876) and Nebelung 

 (1878) on different species, and while the results indicate carotinoids, 

 the solutions examined were not free from other pigments. 



The evidence regarding the character of the carotinoids present is 

 less conclusive. Kraus and Millardet (1868) found that alcoholic 

 extracts of Oscillatoria, Nostoc and Calothrix species responded to the 

 alcohol-brn/uir separation, leaving a yellow pigment behind in the 

 alcohol. Nageli's designation, phycoxanthin, was adopted for the 

 pigment remaining in the alcohol. Kraus (1872), however, later rec- 

 ognized that more than one pigment was probably present in these 



