118 CAROTINOIDS AND RELATED PIGMENTS 



ment, which appears to be the chief one present, differing from nec- 

 triin in the position and number of the absorption bands (polystig- 

 min, as Zopf calls it, showing only two even in carbon disulfide), and 

 also in that the barium compound is soluble in ether, chloroform, car- 

 bon disulfide and alcohol. Zopf's examination of Polystigma ochra- 

 ceum, which has more of a yellow than a red color, showed an abun- 

 dance of yellow "carotin," which was regarded as produced in the 

 fungus cells. No red pigment was found, but the fungus was not de- 

 colorized after the extraction of the carotinoid, but was left a reddish- 

 brown color which could be extracted by dilute ammonium hydroxide. 



Van Wisselingh (1915) made a special examination of the micro- 

 chemical crystals formed in Spaerostilbe coccaphila, a red fungus 

 found on fallen trees. The fungus itself contains red, fat-like globules. 

 Violet-red crystals were produced in the Molisch test, which gave the 

 carotinoid color reactions and dissolved readily in the phenol-glycerin 

 reagent which appears to be specific for xanthophyll. 



The Phycomycetes. This class of fungi includes the molds, the 

 mildews and the yeasts and thus contains many species of plants of 

 great importance. One does not ordinarily associate carotinoid colors 

 with these fungi, and the presence of such pigments does not, in fact, 

 appear to be common. Carotinoids have been demonstrated to be 

 present, however, in several instances. 



Zopf (1892b) was able to extract a carotinoid from -three species 

 of Pilobolus, namely, P. crystallinus, P. Kleinii and P. Oedipus, which 

 gave the lipocyan reaction, the lipochrome reaction with iodine, and 

 also showed absorption bands in petroleum ether at 484-469^ and 

 452-439^.1, which correspond closely with xanthophyll. The first two 

 species flourish on fresh horse dung, the last on dung or rotting algae. 

 Zopf also stated (1892b) that Pleotrachelus fulgens, a reddish-brown 

 species of another order, is- a carotin (oid) former, but the evidence 

 for this was not presented. 



Kohl (1902) confirmed the presence of carotinoids in Philobolus 

 species using the Molisch test, and also showed the same pigments to 

 be present in Mucor species and in Chytridium. 



Van Wisselingh (1915) included Mucor flavus Bainer in his micro- 

 chemical studies. Orange-yellow crystals were secured by the Molisch 

 method, which gave the carotinoid color reactions with nitric acid 

 and with bromine. 



The Myxomycetes. These fungi form a distinct, independent group 

 of plants, commonly known as slime molds, and were formerly classi- 



