CONCLUSION 295 



of V. H. Blackman has shown that in the Uredineae, the 

 secidium is to be regarded as a sexually produced fruit, 

 comparable to an ascus-fructifi cation, while the spermo- 

 gonia represent male organs which have lost their 

 function. The uredospores, teleutospores, and sporidia, 

 however, are all of the nature of conidia. 



The Uredineae are adapted to a strictly parasitic mode 

 of life, and in habit differ greatly from the Basidiomy- 

 cetes, especially if we consider a highly organised repre- 

 sentative of the latter, such as the Mushroom. Yet the 

 complex fructifications of these highest of the Fungi are 

 nothing but elaborated conidiophores, and the basidium 

 itself appears to be comparable to a teleutospore germi- 

 nating in situ, a conclusion which is strikingly confirmed 

 by the occurrence of nuclear fusion, alike in the teleuto- 

 spore and the basidium. 



We see then that the Fungi form by themselves a 

 highly-complex cycle of relationship, touching the lower 

 Algae at one or two points, but otherwise distinct from 

 the rest of the vegetable kingdom. Sexuality has proved 

 to be far more general among this mass of saprophytic 

 and parasitic organisms than was once supposed, though 

 it often assumes a curiously reduced form comparable to 

 the fusion of nuclei in apogamous Fern-prothalli. 



We must now retrace our steps to the Algae. The 

 Red Seaweeds form a perfectly definite group by them- 

 selves, without clear connections either below or above. 

 Callithamnion is a fair average type ; some forms are 

 simpler, especially in the development of the fruit, but 

 even the simplest of the undoubted Florideae are highly- 

 organised plants, quite unlike any other family. Many 

 are much more complex than our type, but they are 

 complex in their own peculiar way, and do not show any 

 transition towards the higher groups of plants. 



