METABOLIC PRODUCTS 293 



similar or the same toxin is present in Clitocyhe illudens, Inocyhe infelix, 

 I. infida, Lactarius torminosus, and B. miniato-olivaceus var. sensibilis 

 (Krieger, 1936; Wolf and Wolf, 1947). 



HelveUic acid is known to be present only in Gyromitra esculenta. Ap- 

 parently there is considerable variability in the reaction of individuals 

 who eat this fungus. Many people have eaten it with no ill effects, 

 although a number of cases of poisoning and even a few deaths have been 

 reported. Helvellic acid is soluble in hot water. Its toxic action is due 

 to its blood-dissolving power. 



While a number of other toxic substances have been detected in the 

 fleshy fungi, the exact identity of most of them is not known. For 

 example, species of Paneolus may cause temporary paralysis or intoxica- 

 tion similar to alcoholic intoxication. Some species of Amanita have 

 been reported to contain other toxins in addition to those discussed above 

 (Fischer, 1918). 



The alkaloids produced by Claviceps purpurea and C. paspali are toxic 

 to man and animals if consumed in large enough quantities. The specific 

 alkaloids produced were mentioned previously. The production of 

 toxins is also common in the genus Fusarium. Gihberella zeae, the cause 

 of scab of small grains, produces toxic substances which are poisonous 

 to livestock fed on scabby grain (Christensen and Kernkamp, 1936). 

 Numerous other fungi which cause plant diseases are known to produce 

 toxic substances which kill the host or modify its activity (see Chap. 17). 



PIGMENTS 



Colored compounds produced by fungi and other organisms are called 

 pigments. In the fungi, some pigments accumulate in the mycelium and 

 spores, while others diffuse into the culture medium. The pigments 

 produced by a fungus are in part determined by genetic factors and in 

 part by the environment. Mycelium, fruit bodies, and spores may be 

 pigmented, or in some species the pigment is confined to the spores. 



Among the fleshy fungi, brown is one of the most common colors of 

 fruit bodies, with yellow, orange, and red being somewhat less common. 

 Often a number of pigments are obviously present. Few fungi are green. 

 Yet, Chlorosplenium aeruginosum produces a green pigment, sylindein 

 (Wolf and Wolf, 1947), which stains the wood in which it grows. Blue- 

 stain fungi (CeratostomeUa spp.) excrete blue pigments into wood. Some 

 species of Boletus produce a blue or bluish-green pigment when bruised or 

 wounded. Tricholoma personatum and Laccaria amythestina are among 

 the mushrooms producing purple or violet pigments. It is said that the 

 red-orange pigment of the fruit bodies of Echinodontium tinctorium, the 

 Indian paint fungus, was used by the Indians as make-up. Few of the 



