THE NORTH AMERICAN SLIME-MOULDS 



INTRODUCTORY 



THE Myxomycetes, or Slime-moulds, include certain very 

 delicate and extremely beautiful fungus-like organisms common 

 in all the moist and wooded regions of the earth. Deriving 

 sustenance, as they for the most part do, in the decomposition- 

 products of organic matter, they are usually to be found upon 

 or near decaying logs, sticks, leaves, and other masses of vege- 

 table detritus, wherever the quantity of such material is suffi- 

 cient to insure continuous moisture. In fruit, however, as will 

 appear hereafter, Slime-moulds may occur on objects of any and 

 every sort. Their minuteness retires them from ordinary ken ; 

 but such is the extreme beauty of their microscopic structure, 

 such the exceeding interest of their life history, that for many 

 years enthusiastic students have found the group one of peculiar 

 fascination, in some respects, at least, the most interesting and 

 remarkable that falls beneath our lenses. 



The Slime-moulds present in the course of their life history 

 two very distinct phases : the vegetative, or growing, assimi- 

 lating phase, and the reproductive. The former is in many 

 cases inconspicuous and therefore unobserved ; the latter 

 generally receives more or less attention at the hands of the 

 collector of fungi. The vegetative phase differs from the corre- 

 spondent phase of all other plants in that it exhibits extreme 

 simplicity of structure, if structure that may be called which 

 consists of a simple mass of protoplasm destitute of cell-walls, 

 proteid in form and amoeboid in its movements. This phase 

 of the Slime-mould is described as plasmodial, and it is proper 



