2 BOTANICAL GAZETTE [july 



few closely associated. This habit makes the collection of material 

 for developmental study very difficult. Pluteus admirahilis Peck 

 occurs in troops more commonly than most other species, and its 

 bright yellow color makes the young basidiocarps quite easily 

 distinguishable. I began my collection of this species while in the 

 Adirondacks on a collecting trip during July 1916. A large part of 

 the material was collected from troops where only 3 or 4 basidiocarps 

 of suitable age were obtainable. The largest individual collection 

 was secured after my return to Ithaca, in the Van Samtford woods 

 near Freeville, New York, during the latter part of August 1916. 



The material for the study of Tuharia furfuracea Gill was col- 

 lected in Cascadilla ravine, and along the banks of Fall Creek, on the 

 Cornell University campus, during the early summer of 1916, where 

 the plants were growing very abundantly on the leaf mold and 

 loam in a small wood. The plants occurred in troops upon an 

 abundant mycelium which permeated the substratum. All stages 

 in development were to be found upon this mycehum when the 

 fruits first began to appear. 



The material for the study of both genera was fixed in chrom- 

 acetic and Benda's fluids, cleared in cedar oil, and imbedded and 

 sectioned in paraffin. 



Pluteus admirabilis 



ORIGIN OF HYMENOPHORE 



No fruit body was obtained before the beginning of any differ- 

 entiation had taken place in the primordium of the basidiocarp. 

 The youngest stage secured (fig. i) was a little over 0.5 mm. in 

 height and already showed a differentiation into primordia of 

 stipe, pileus, and hymenophore. The primordium of the stipe is 

 made up of loosely interwoven, much branched filaments, uniformly 

 about 3 M in diameter, which become less interwoven and show 

 many free ends near the surface, as can be seen in fig. 29, a higher 

 magnification of the same fruit body. This tissue gradually passes 

 into that of the primordium of the pileus, which at the base has 

 the same structure as the primordium of the stipe, but soon opens 

 out into a less interwoven tissue in which the filaments lie almost 

 parallel to each other and radiate in a fanlike manner, with free 



