222 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



gressive differentiation of the pileus area from its apex, followed 

 by the differentiation of the hymenophore fundament, represented 

 by Lepiota cristata and L. seminuda. 



A similar type is presented in the development of Rozites 

 gongylophora according to the account by A. Moller ('93, p. 70), 

 who describes also the presence of an outer envelope (homologous 

 with the blematogen) and an inner envelope (which forms the 

 partial veil proper). His description of the origin of the hymeno- 

 phore primordium, the palisade stage, the origin of the general 

 annular prelamellar cavity, as well as the origin of the gills by 

 downward growing radial processes of the palisade stage, is in 

 entire harmony with the account given here of the procedure in 

 Lepiota cristata and L. seminuda. The morphology of Rozites 

 gongylophora is that of a typical Lepiota and the spores examined 

 in water are white, although the spore mass is bright ochre color. 



In some of these species the precedence in the differentiation 

 of one or another part of the fruit body seems to vary to some ex- 

 tent. In Agaricus arvensis it appears that the pileus area may be 

 differentiated simultaneously with the hymenophore primordium, 

 and in Lepiota clypeolaria it would appear that the stem and 

 pileus fundaments may be differentiated simultaneously or possibly 

 in some cases the stem primordium may precede that of the 

 pileus. 



Another type is described by Fischer ('09) in Armillaria 

 mucida. He states that the pileus is differentiated first by the 

 appearance of a palisade layer of radial hyphae at the apex of the 

 basidiocarp primordium, and underneath the very thin "uni- 

 versal veil" (Pprotoblem). The organization of the palisade 

 progresses down the sides and then inward over the under surface 

 of the pileus, there forming the palisade stage of the hymenophore. 

 This type is so unusual that its confirmation would seem desirable. 

 It may be pointed out, however, that some species of the agarics, 

 notably some species in the genus Marasmius, have similar 

 cystidia in the hymenium and surface of the pileus, which suggests 

 a possible close relation in the origin of these surfaces. From the 

 account given by Fischer it would seem that the "unixersal 

 veil" which he describes is a protoblem and that the l)lematogen 

 is absent, since the pileus surface and hymenophore primordium 

 are continuous. Thus, leaving the protoblem out of account, the 



