Fruiting relations of some Mycetozoa 

 Robertson Pratt 



Biological literature is rich in studies of the mycetozoa, or 

 the so-called slime molds. Accounts of their life histories and 

 habits are to be found in zoological as well as in botanical pub- 

 lications, since some zoologists maintain that these organisms 

 should be classed with the protozoa. Most of the literature, 

 however, is found in botanical papers, and as Arthur Lister has 

 pointed out, their study has usually been associated with that 

 of fungi. The term "mycetozoa," which is descriptive of the 

 principal characteristics of these organisms, was introduced by 

 DeBary (1860) as a designation for the group. 



The present report is intended merely as a brief note on the 

 substrata on which some of these myxomycetes are found when 

 fruiting in the field. Therefore a complete review of the myce- 

 tozoan literature is unnecessary. For a resume of the literature 

 concerning these organisms the reader is referred to A. Lister's 

 monograph (1925). 



Usually when authors describing slime molds have men- 

 tioned the type of substratum on which the fruiting structures 

 are found, they have been content to describe it merely as dead 

 wood, dead leaves, or dead herbaceous stems; or they have used 

 some other terse phrase equally indefinite. In some instances the 

 description has been more specific in that the kind of wood or 

 leaf is mentioned. Possibly in some cases there is a definite as- 

 sociation between the fruiting condition of a slime mold and a 

 particular species of wood or leaf. Observations in the field, indi- 

 cate, however, that for many species of mycetozoa the texture 

 of the substratum on which they fruit is more constant than the 

 species of the substratum. This would seem to indicate that the 

 moisture content of the substratum, rather than the species, de- 

 termines whether or not a particular location is suitable for the 

 fruiting of a. given myxomycete. For example, some species of 

 the elegant Stemonitis apparently require a situation which is 

 not too wet. They are found most frequently in more or less 

 exposed situations, raised somewhat above ground level, and 

 therefore not exceedingly wet. The writer has found Stemonitis 

 fusca on bare rock, on bracket fungi, and on fairly dry pieces 



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