.FUNG[. 89 



to one another, and form a flat body (e.g. Exobasidium vaccinii, 

 Hypochnus ; among the Phycomycetes, Empusa nniscce and Cystopus). 

 (b) In a HIGHER form the conidial-layers are thick, felted threads 

 (stroma) inserted between the mycelium and the hymenium (i.e. 

 the region of the conidiophores). Examples are found in a section 

 of the Pyrenomycetes (Fig. 122). (c) The HIGHEST form has the 

 basiJiaJ -layer, that is a conidial-layer with more highly developed 

 conidiophores (basidia). The basidial-layer, with stroma, and 

 the hymeniurn (region of the basidia), forms the basidio-fructifica- 

 tion, which is branched in the Clavariacea?, and hat-shaped in 

 other Hymenomycetes (in these groups the hymenium is confined 

 to the lower side of the pileus). 



The hymenium of the conidial-layer and basidial-layer is com- 

 posed entirely of conidiophores, or of conidiophores and sterile 

 hyphre (paraphyses) which are probably always unicellular. 

 Paraphyses are found in Entomophthora radicans, and in certain 

 Basidiomycetes (e.g. Corticium'). 



3. CONIDIOCARPS (pycmdia). A special covering surrounds the 

 conidia-foi-ming elements. The inner side of this covering 

 (peridium) bears the hymenium, i.e. those elements from which 

 the conidia are abstracted. The conidiocarps arise either imme- 

 diately from the hyphoe or from a stroma in which they are 

 generally embedded. Conidiocarps are entirely wanting in the 

 Phycomycetes. On the other hand they are found among the 

 Ascomycetes and Basidiomycetes, and in the latter group the 

 conidiocarps contain more highly differentiated conidiophores 

 (basidia) and are known as hasidiocarps. Conidiocarps with simple 

 conidiophores, are found only among the Basidiomycetes, in the 

 Uredinacese, and in Craterocolla cerasi. In the Ascomycetes (Figs. 

 120 cZ, e ; 117 a, b ; 123 a ; 124? 6) the conidiocarps are visible, as 

 points, to the naked eye, while the basidiocarps of the Basidiomy- 

 cetes (Figs. 170, 171, 173-176, 178-180) vary from the size of a 

 pea to that of a child's head. The " spermogonia " of the 

 Ascomycetes and Lichenes, are conidiocarps with small conidia 

 (microconidia) which germinate sometimes more slowly than other 

 conidia, and formerly were erroneously considered as male repro- 

 ductive cells, and called spermatia. 



The conidia of the Fungi are not primitive structures. The 

 comparison of the sporangia and conidia among the Zygomycetes, 

 and among the species of the genus Peronospora shows, that the 

 conidia are aberrant formations, and that they have arisen through 



