Genus Lepiola 315 



out the section, at least it may be assumed that only this type 

 of species should be included in this section. As constituted in 

 the present paper, it will be seen that the presence of a definite 

 annulus of the truly membranous type is the fundamental basis 

 of the section referred to. 



The species which come under the section Pruinosae, as 

 limited in this paper, should have a pulverulent, flocculose or 

 obsolete covering on the surface of the pileus and on the stem, 

 and this covering is assumed to be derived from the blcmatogen. 

 In addition, the annulus is not truly membranous, or at least it 

 is delicate and poorly developed. Here again, one can not at 

 present be consistent, because of the incomplete data for quite 

 a number of species. Atkinson studied the development of 

 Lepiota seminuda, as a representative of this group. He found 

 the mealiness due to the breaking down of the blematogcn tissue, 

 its hyphal cells separating into turgid cells. Of course, not all 

 the species included below in this section have this type of cap- 

 and stem-covering, and doubtless a number of groupings can be 

 made when more developmental studies give us the details. 

 There is, however, a reasonable limit to the subdividing that maj^ 

 be done, and relations will have to be worked out with some 

 degree of conservatism. 



No studies of any consequence have yet been made of the 

 development from the early stages, for the species belonging to 

 our other sections. In the Lubricae, with a gelatinizing and 

 therefore viscid or glutinous outer layer on both pileus and stem, 

 it seems clear that a universal veil of the blcmatogen type is 

 present. There is reason to suspect that such a layer is well 

 developed in the sections Asperae and most of the Procerae- 

 annulosae. The last group has usually been placed under two 

 sections, but the structures, during development, in spite of the 

 size of the plants, have not been sufficiently studied in many 

 cases, so that no acceptable fine of separation seems possible at 

 present. 



Many of the species of Lepiota are quite peculiar in their 

 fruiting habits. There are, in a broad sense, two types with 

 reference to habitat; those which appear on cultivated land. 



