6 Mycetozoa of North America 



America, and are not included. There are some exceptions in the 

 various divisions of the classification, but on the whole it is very 

 satisfactory and workable, so that the great majority of the species 

 can be determined without much trouble if the specimens are 

 fairly typical. All sorts of intermediate forms do occur; these 

 present problems, and are of great interest from an evolutionary 

 point of view. 



In studying the Mycetozoa for the determination of species, 

 certain field conditions should be noted, such as the size of the 

 fructification, the habitat, the color of the plasmodium if seen, 

 and whether the sporangia are closely aggregated or scattered. 

 The microscopical examination, at first, should be as an opaque 

 object, with a few of the sporangia blown out by a small hand- 

 blower to free them from spores. After that a few of the blown 

 out sporangia should be picked ofl^, placed on a slide in water 

 under a cover glass, and studied by transmitted light. The water 

 may not permeate sufficiently to drive out the air, in which case a 

 mixture of water and alcohol will work better. Badly contracted 

 spores may be swollen rapidly by the admission of a drop of a five 

 per cent solution of potassium hydrate in water, but this has a 

 tendency to alter the color of the spores of certain species. Per- 

 manent preparations may be mounted in glycerine, glycerine 

 jelly, or Canada balsam — remembering that glycerine is not suit- 

 able for forms with lime — but is only required for certain purposes, 

 and the examination in water is usually all that is necessary. 

 The main characters recognized in the classifications of species 

 are the shape, the color, the wall or peridium, and the spores; 

 the absence or presence of lime, stalk, columella, and capillitium; 

 and the form, size, color, and markings that may apply to them. 

 There are others, but those must be studied in the species 

 descriptions. 



The collection and study of the Mycetozoa presents an almost 

 untrodden field. There have been few students, and there are 

 few today, as compared with the many in other pursuits. There 

 are opportunities for research, not only in the morphology and 

 physiology of the group, but in the taxonomy. The roaming and 

 collecting through the forests is a healthy hobby, with many 

 thrills that come when an interesting form is found. The beauty 

 of the fruiting bodies, with their variety of form and color, and 

 the study of their curious life history, provide fascinating subjects 

 for the microscopist. 



