kEfORt OF THE StATE BOTANIST I917 ^ 



fold. First, it brings together in one paper all of Peck's descrip- 

 tions of Porias — a convenience that will be appreciated by those 

 who have had to turn from one report to another to locate them. 

 Second, it enables the student to see at a glance what in this paper 

 has been added to each of Peck's descriptions. 



2 A section has been headed Notes and contains a more extended 

 account of the present condition of the type collection, characters 

 not included by Peck, explanation of discrepancies of one form or 

 another where such occur, and observations on the distinguishing 

 characteristics and probable relationships of the species. 



3 The characters brought out in the two preceding sections are 

 combined into a technical Redescription. This of course, involves 

 repetition, but it puts into a paragraph a concise description of each 

 species and makes it available for future use. 



4 Each species is illustrated as fully as material permits. Three 

 types of illustrations are used. (a) Natural size photographs 

 (unless otherwise noted) of at least a part of the material in the 

 type collection. Where possible this material was chosen so as to 

 show as wide a range as possible in the variations of the species. 

 In some instances material is extremely scanty and the results 

 more or less unsatisfactory, {b) Microphotographs of sections 

 through the hymenium of each species. Wherever possible these 

 are from cross-section preparations but in a few cases the tubes 

 were so short that vertical sections were resorted to. In passing 

 judgment on these microphotographs it should be borne in mind 

 that they are from free-hand sections, made by the writer, and cut 

 and mounted as described in a previous paper (Ann. Missouri 

 Botanical Garden, 2: 676. 1915), but stained in a i per cent solu- 

 tion of water eosin. The mounts were made in 66 per cent glycerine 

 to which a few drops of a 10 per cent solution of acetic acid had 

 been added. The acid prevents the glycerine from extracting the 

 stain from the sections. It should also be remembered that the 

 dried material from which these sections are made has been in the 

 herbarium for as many as forty years in some cases, and moreover 

 that in some cases type material is extremely scanty and is too 

 valuable to be diminished to any extent by continued sectioning in 

 an attempt to obtain a section of extreme thinness. It is hoped, 

 however, that these sections will show in a suitable manner the 

 relative size of the pores, the relative compactness of the dissepi- 

 ments, and the cystidia, where such are present. These photographs 

 are all magnified to the same extent, namely, about 160 diameters 

 unless otherwise indicated, and consequently are directly comparable 



