12 THE MYXOMYCETES 



Specimens collected should be placed immediately in boxes in such 

 a way as to suffer no injury in transport; beautiful material is often 

 ruined by lack of care on the part of the collector. Once at the herba- 

 rium, specimens may be mounted by gluing the supporting material to 

 the bottom of a small box. Boxes of uniform size and depth may be 

 secured for the purpose. Some collectors prefer to fasten the specimen 

 to a stiff paper, of a size to be pressed into the box snugly, but which 

 may be removed at pleasure. Every care must in any case be taken to 

 exclude insects. Against such depredators occasional baking of the 

 boxes on the steam radiator in winter is found to be an efficient remedy, 

 or paradichlorobenzene may be sprinkled in the boxes or herbarium 

 cases two or three times a year. In the United States National Herba- 

 rium specimens are mounted on the inside of the cover of boxes 

 1% X 4 X % inches, the label and the specimen thus being in- 

 separable. The shallow cover permits ready examination of the mate- 

 rial with lens or binocular microscope. Such boxes fit snugly in a shal- 

 low box the size of an herbarium sheet, five of which fit easily into a 

 standard herbarium shelf. This method, while somewhat wasteful 

 of space in the case of very small collections, is admirably suited to 

 the great majority of collections, and permits their riling in strict order. 

 It has been adopted for the bulk of the collections in the herbarium of 

 the State University of Iowa. This collection, which has served as the 

 basis for the present work, contains, in addition to the accumulations 

 of many years by the authors and their colleagues and associates, the 

 invaluable Morgan and Wingate collections. Included also are note- 

 worthy gatherings by Ellis, Farlow, Shimek, Rex, Bilgram, Hagelstein, 

 Harvey, Bethel, H. C. Gilbert and O. A. Plunkett in America, and 

 Sydow, Japp, Brandza and Meylan in Europe. An interesting series of 

 duplicates of the collections of O. F. Cook from Liberia, secured by 

 exchange with the United States National Herbarium, is also included. 

 The study of this material has been checked by examination of that in 

 other institutions, particularly the splendid collection in the United 

 States National Herbarium. Mr. Lister and Miss Lister have courte- 

 ously given portions of certain critical or doubtful species for compari- 

 son. 



For simple microscopic examination it will be found convenient 

 first to wet the material with alcohol on the slide, then with a weak 

 solution of potassium hydroxide (2-3%) to cause the spores and other 

 structures to assume proper plumpness. A little glycerine may be 

 added or run under the cover if it is desired to preserve the material 

 for further or prolonged study. For permanent mounting nothing is 

 better than glycerine jelly in most cases. As a preparation the material 



