312 MYCORRHIZAE AND MYCOTROPHY 



in those inoculated with Boletus viscidus. The differences would 

 no doubt have been greater if he had not used manure. Australian 

 mvcorrhizal fungi might also be expected to have been better 

 suited as inoculum. 



These observations and experiments, although not numerous, 

 indicate several very obvious conclusions. In the first place, at- 

 tempts to exclude diseases and pests from prairie or other treeless 

 regions by starting nurseries from seed are doomed to failure 

 unless suitable mvcorrhizae producers are introduced. Second, 

 mvcorrhizal fungi perish in areas that have been long denuded, 

 and thev must be reintroduced if the areas are to be reforested. 

 Third, planting failure can result if the environment of the plant- 

 ing site is unfavorable for the growth of the fungal component. 

 This conclusion is supported by the experiments of Romell 

 [Hatch (1937)], who found that mycorrhizal fungi may be more 

 exacting in their site requirements than are the trees with which 

 they became established in this mycorrhizal relationship. 



In the light of these studies on mycorrhizae, the fleshy fungi 

 growing on the forest floor have uses aside from supplying the 

 mycologist with objects with which he may occupy his time, or 

 the layman with victims against which he may employ his toe to 

 vent his pent-up emotions. 



For use in silviculture further knowledge should be sought by 

 attempting to synthesize mycorrhizae from fleshy fungi and for- 

 est trees. Studies of this sort are still too limited in number and 

 scope. The value of such work is indicated by Alodess (1941). 

 He employed pure cultures of Hymenomycetes and Gastromy- 

 cetes with pines and spruce, finding that Scots pine developed 

 mycorrhizae with Amanita mappa, A. musctiria, A. pantherina, 

 Boletus flavidus, Entoloma rhodopoliuvh Lactarius helvus, Paxil- 

 lus primulas, Rhizopogon luteolus, R. roseolus, Scleroderma au- 

 rantium, Tricholoma albobrumieum, T. imbricatum, T. pessunda- 

 tinih and T. vacciniwm, and that Picea abies synthesized mycor- 

 rhizae with each of the species of Amanita, Boletus, Lactarius, 

 Tricholoma, and Scleroderma that has been mentioned. 



Tuberizatiox. From time to time evidence has been presented 

 which indicates that tuberization in certain plants may be induced 

 by mvcorrhizal fungi. In this connection the work of Bernard 

 on the group of tuberous orchids is of especial significance. She 

 found that the seeds of Bletilla, sown aseptically, develop into 



