270 STRUCTURAL BOTANY 



gills of a Mushroom. Some idea of their multitude may 

 be obtained by cutting off the pileus of an Agaricus and 

 laying it, gills downward, on a sheet of white paper. 

 If it be removed after a time an exact print of the gills 

 will be found on the paper, in the form of a fine powdery 

 deposit of spores which have fallen from them. 



Until recently, nothing satisfactory was known as to 

 the germination of the spores of the Mushroom. Of 

 late years, however, Mushrooms have been successfully 

 raised from spores in Paris ; the entire development, up 

 to the formation of ripe fructifications, takes from six 

 to seven months. As a rule they are raised from the 

 mycelium or " spawn." 



The basidial fructification is quite distinct from that 

 of any other group of Fungi which we have described. 

 There are, however, a number of transitional forms 

 among the lower Basidiomycetes which appear to connect 

 that order with the Uredineaj, and it has been suggested 

 that the basidium of the Mushroom group is homologous 

 with the pro-mycelium produced from the teleutospores 

 of the latter family, the basidiospores corresponding to 

 the sporidia. There are some UredineaB, such as the 

 Piiccinia so common on hollyhocks (P. Malvacearum), in 

 which the teleutospores germinate in situ, i.e. while still 

 in the sorus and attached to the mycelium. In this 

 case the resemblance of the pro-mycelium to the basidia 

 of some of the simpler Basidiomycetes is very striking, 

 but unfortunately we have no space for the description 

 of the supposed intermediate types. 



In Fig. 107 the development of the Mushroom-fruit 

 is illustrated. The young Mushroom arises from a 

 tangle of hyphse borne on a strand of mycelium. The 

 intertwined hyphae group themselves into a tissue, thus 



