296 PHYLOGENY 



to these influences are also frequent, viz. size of podetia, proliferation and the 

 production more or less of soredia or of squamules on the podetia, though 

 only in connection with species in which these variations are already an 

 acquired character. The squamules on the podetium more or less repeat 

 the form of the basal squamules. 



7. PODETIAL DEVELOPMENT AND SPORE-DISSEMINATION. In a recent 

 paper by Hans Sattler 1 the problem of podetial development in Cladonia 

 is viewed from a different standpoint. He holds that as the podetia are 

 apothecial stalks, their service to the plant consists in the raising of the 

 mature fruit in order to secure a wide distribution of the spores, and that 

 changes in the form of the podetium are therefore but new adaptations for 

 the more efficient discharge of this function. 



Following out this idea he regards as the more primitive forms those in 

 which both the spermogonia, as male reproductive bodies, and the carpogonia 

 occur on the primary thallus, ascogonia and trichogynes being formed before 

 the podetium emerges from the thallus. Fertilization thus must take place 

 at a very early period, though the ultimate fruiting stage may be long 

 delayed. Sattler considers that any doubt as to actual fertilization is without 

 bearing on the question, as sexuality he holds must have originally existed 

 and must have directed the course of evolution in the reproductive bodies. 

 In this primitive group, called by him the "Floerkeana" group, the podetia 

 are always short and simple, they are terminated by the apothecium and 

 no scyphi are formed (Cl. Floerkeana, Cl. leptophylla, Cl. cariosa, Cl. caespr- 

 ticia, CL papillaria, etc.). 



In his second or "pyxidata" group, he places those species in which the 

 apothecia are borne at the edge of a scyphus. That structure he follows 

 Wainio in regarding as a morphological reaction on the failure of the first 

 formed apical apothecium: it is, he adds, a new thallus in the form of a 

 spreading cup and bears, as did the primary thallus, both the female primordia 

 and the spermogonia. In some species, such as Cl. foliacea, there may be 

 either scyphous or ascyphous podetia, and spermogonia normally accompany 

 the carpogonium appearing accordingly along with it either on the squamule 

 or on the scyphus. 



As the pointed podetia are the more primitive, Sattler points out that 

 they may reappear as retrogressive structures, and have so appeared in the 

 "pyxidata" group in such species as Cl. fimbriata. He refers to Wainio's 

 statement that the abortion of the apothecium being a retrogressive anomaly, 

 while scyphus formation is an evolutionary advance, the scyphiferous species 

 present the singular case, "that a progressive transmutation induced by 

 a retrogressive anomaly has become constant" 



1 Sattler 1914. 



