BASIDIOSPORES 37 



British Puccinia Pruni-spinosae and other species, where the 

 short pedicels are all closely bound together in bunches at the 

 base. Paraphyses are naturally not so common in teleuto-sori 

 as with uredospores, since the former do not need such protection, 

 but they are found in P. Sonchi, P. dispersa, P. persistans, etc., 

 although in these cases the so-called paraphyses are not at all 

 of the same character as those found in uredo-sori, e.g. of Puc- 

 cinia Baryi and others. When the teleutospore of a normally 

 two-celled species becomes one-celled (by the omission of the 

 last cell-division), it is called a mesospore : the mesospores of 

 Puccinia are practically identical with the teleutospores of 

 Uromyces and germinate like them. 



BASIDIOSPORES. 



All normal teleutospores develop under natural conditions 

 in the same way ; the cell-contents divide themselves into four 

 parts, by a heterotype followed immediately by a homotype 

 mitosis. 



This formation of what are really (and might with ad- 

 vantage be called) tetraspores can take place in two ways : — the 

 "basidium" can arise within the teleutospore-cell or outside it. 

 The first method is the more primitive, the second is an 

 adaptation to the tough cutinised or chitinous exospore of the 

 more advanced types. In the Coleosporiaceas the teleutospore, 

 i.e. the tetraspore-mother-cell, divides into four superposed cells 

 (like the tetraspores of Gorallina) while still in the sorus, during 

 the autumn ; each cell (spore) germinates, in late autumn, by 

 protruding a sterigma through the thin gelatinous wall of the 

 teleutospore and forming a basidiospore (conidium) at its apex. 

 Zaghouania shows an intermediate form of germination. But 

 in all the other families the cell-contents of the teleutospore, 

 clothed only in a thin endospore, pass out through a germ -pore 

 in the form of a longer or shorter tube (" basidium ") ; the 

 contents pass to the distal end of this, and are there divided 

 into four oblong cells. The median septum is sometimes formed 

 first, and the two lateral ones after. In water the " basidium " 

 is usually long, in air it is short. In the absence of sufficient 



