ATKINSON: LEPIOTA CRISTATA AND L. SEMINUDA 223 



origin of the hymenophore would be similar to the method in 

 certain gymnocarp forms. 



Summary 



1. In Lepiota cristata the stem fundament is first organized in 

 the base of the young basidiocarp. The pileus fundament is 

 later organized by progressive growth and differentiation from 

 the stem apex, the stem and pileus fundaments together forming 

 a sheaf-like internal area enveloped by ground tissue and the 

 blematogen. The organization of the stem and pileus funda- 

 ments in Lepiota seminiida is probably similar, for the fundament 

 of the two forms a similar internal sheaf-like area. 



2. The hymenophore primordium in both species arises by 

 numerous branches rich in protoplasm, extending outward and 

 downward from the lower outer margin of the pileus primordium. 

 The pileus margin is also organized in connection with the hymeno- 

 phore fundament. Together they form an internal, annular zone 

 of new growth. Continued marginal growth by the origin of 

 new elements extends the hymenophore and pileus margin in a 

 centrifugal direction. 



3. The primordial stage of the hymenophore is characterized 

 by parallel slender hyphae whose general direction of growth is 

 downward, but it becomes arched by epinastic growth of the pileus. 

 In the primordial stage of the hymenophore the lower surface is 

 loose and velvety, or fimbriate, and the free ends of the hyphae 

 lack register, i. e., they show an unequal reach. The primordial 

 stage passes to the level palisade stage of the hymenophore by 

 increase in number and thickness of the hyphal branches, and by 

 the register of their free ends, so that a compact even under surface 

 is formed. This begins next the stem and progresses in a centrif- 

 ugal direction toward the margin of the pileus. 



4. The lamellae arise as downward growing radial salients of 

 the level palisade. The gill salients begin on the older portions 

 of the hymenophore palisade and proceed in a centrifugal direction 

 toward the margin of the pileus. Thus, at an intermediate stage 

 of development of the young basidiocarp, three stages of hymeno- 

 phore development are present, the primordial zone next the 

 pileus margin, preceded by the level palisade zone, and this by 

 the zone of young gill salients next the stem. These progress in a 

 centrifugal direction until the primordial stage is transformed into 

 the level palisade and the latter into the gill salients. 



