CAROTINOIDS IN Till- CRYPTOGAMS 115 



more recently by van Wisselingh (1915) who was able to secure 

 crystals of pigment by the Molisch inicroclR-inical test. The latter 

 invigilator states that about twenty-live fungi which he examined 

 by this method failed to respond to the test, but mentions .-.pirifically 

 only those which responded. Special attention was given to the crys- 

 tals produced in the case of Calocera viscosa and Ducryomyces 

 stillatus. From the former a heavy precipitation of orange colored 

 crystals was secured from a section between the hypens. These gave 

 all the carotinoid color reactions, and the crystals dissolved slowly in 

 phenol-glycerin, indicating a xanthophyll-like pigment. ('. cornea 

 and C. palmata gave like results. In the case of Dacryomyccs stil- 

 latus crystals of a similar color were secured, as well as red colored 

 crystals and orange-yellow aggregates, suggesting the possibility of 

 several carotinoids being present. 



Particularly interesting is the abundant evidence that the coloring 

 matter of the rust fungi is carotinoid in nature. Bachmann (1886) 

 first called attention to the fact that the rusts from several different 

 hosts owe their color to orange or yellow oil globules containing 

 unsaponifiable chromolipoids. The pigment was isolated by cutting 

 out the rust spots, extracting them with ether or hot alcohol, saponify- 

 ing the extract, and extracting the soap with petroleum ether. The 

 positions of the spectroscopic absorption bands of the extracts thus 

 obtained correspond closely with those of carotin. The residues from 

 the extracts gave the usual color reactions with concentrated sulfuric 

 acid and iodine. Miillcr (1886) observed that red pigment crystals 

 appeared in the spores of certain rusts when placed in glycerin. 

 Zopf (1890) held that these were due to a pigment other than lipo- 

 chrome, but that the fungi contain the lipochrome as well as the 

 special red pigment. Bertrand and Poirault (1892), however, who 

 observed the same phenomenon in the rusts examined by Miiller, as 

 well as other species, regarded the red crystals to be due to cholesterol 

 colored by carotin, inasmuch as identical crystals are formed when the 

 pollen grains of Verbascum thapsiforme L. (mullein) are mounted 

 in glycerin. In view of the observations of Bachmann pointing con- 

 clusively to the presence of carotinoids in the rusts, it seems likely 

 that pigments of this type are involved in the crystals observed by 

 Miiller and by Bertrand and Poirault. It should be noted, however, 

 that the uredo spores of these fungi, which is the chief pigmented 

 stage in their development, are not colored alike for the various 

 species, the color varying from yellow to reddish orange. The winter 



