CHAPTER II 



THE TELEUTOSPORE AND THE CURVATURE OF THE 



BASIDIUM 



A Comparison of the Mechanism for the Production and Liberation of Basidio&pores 

 in the Uredineae and the Hymenomycetes — The Shape and Position of the 

 Basidia of Puccinia Malvacearum during Spore -discharge 



A Comparison of the Mechanism for the Production and Libera- 

 tion of Basidiospores in the Uredineae and the Hymenomycetes. — 

 The Uredineae and the Hymenomycetes both belong to the great 

 group Basidiomycetes because they both develop basidia and 

 spores. The manner in which the Uredineae and the Hymeno- 

 mycetes became differentiated from one another in the course 

 of evolution is still a matter of controversy, and writers have 

 constructed a number of phylogenetic trees corresponding to 

 their various views ; but it is generally agreed that in both 

 groups the basidiospores are phylogenetically the most primitive 

 organs of dissemination. It is further agreed that the conidia and 

 chlamydospores which are produced in connection with the 

 mycelium or the fruit-body of certain Hymenomycetes, and also 

 the uredospores and aecidiospores which are produced by many 

 Uredineae, are, relatively to the basidiospores, of later origin. It 

 is possible that the uredospores and aecidiospores are modified 

 teleutospores ; but with these secondary organs of dissemination we 

 shall not now concern ourselves. In what follows we shall confine 

 our attention to the basidiospores. 



The Uredineae are all parasites, entirely dependent on their 

 host-plants. On the other hand, the Hymenomycetes, with com- 

 paratively rare exceptions, are saprophytes. It seems to me that 

 it is this different mode of life which has led to the difference in the 

 manner in which the basidiospores are produced in the two groups. 



