6 



aJCJDIOSPORES 



same time, shows thai they mutually influence each other, and 

 implies thai all the cell-processes which :_, r " on are likewise 

 under their common control. 



The upper cell, cul off from the fusion-cell, is the aecidio- 

 spore- mother-cell ; the lower grows a little longer and then 

 divides again in the same way, and thus a vertical series of 



aecidiospore-mother-cells is formed, the 

 oldest at the to]>. Each of the aecidio- 

 spon-mol her-cells, as soon as produced, 

 nits off, by conjugate division, a small 

 (•"11 below, called the intercalary cell; 

 this soon becomes disorganised and 

 disappears, while the other portion 

 becomes the aecidiospore. Thus the 

 chain at first consists of alternations 

 of a?cidiospores and abortive spores, 

 both containing two nuclei (Fig. 4<) ; 

 the function of the latter may be, 

 by their disintegration, to enable the 

 ajcidiospores to separate more easily 

 from one another, and thus to aid dis- 

 persion by the wind. 



Thr ficridiiim is composed of cells 

 homologous with the spore-mother- 

 cells. They arise from basal cells con- 

 taining two nuclei in exactly the same 

 way ; occasionally even an intercalary 

 cell is cut off, but it does not dis- 

 integrate. All of them thicken their 

 walls and remain in close contact with one another; ultimately 

 their contents disappear ( Fi-. '>). The central part of the 

 dome-shaped peridium is composed of the terminal cells of 

 the central spore-bearing hyphse ; they are probably less closely 

 connected with one another, and the peridium ultimately 

 bursts at that point. 



The spores, if placed in a damp atmosphere, germinate 

 readily when mature and fresh. Only those spores which are 

 at the top of the chains and can be shaken out easily by 



Fig. 4. /'. Caricis. Chain of 

 young recidiospores, x 500. 

 ", fusion-tissoe; //, basal 

 (fusion) cell, with con- 

 jugate nuclei ; c, aecidio- 

 Bpore-mother-cell ; d. in- 

 tercalary cell ; e, yonng 

 a eidiospore. 



