THE FUNGI 257 



These cells are the sporidia] the stalks on which they 

 are borne are called the sterigmata. Hence we see that 

 the teleutospore is incapable of directly reproducing the 

 typical form of the Fungus, for it only gives rise to a 

 rudimentary mycelium, which proceeds at once to form yet 

 another kind of spore. The sporidia become detached 

 from their stalks, and are capable of direct germination ; 

 but if they do not happen to be carried by the wind to 

 their proper host-plant, they form only a very short 

 hypha, which at once gives rise to a secondary sporidium 

 (Fig. 102, D), so as to gain another chance of successful 

 dissemination. 



The sporidia, whether primary or secondary, are quite 

 incapable of infecting any plant of the Grass Family. 

 They are dependent upon a totally different kind of host, 

 namely, the Barberry (Berberis vulgaris) or some of its 

 allies. The sporidium, if it germinates on the leaf 

 of a Barberry bush, sends out a hypha which is 

 able to penetrate the cuticle, and therefore does 

 not need to make use of the stornata, in order to 

 effect an entrance into the tissues of its victim. 

 In this respect the germinating sporidium differs 

 from all the other forms of spore in this Fungus. 

 When the mycelium is once started, it spreads through 

 the tissues of the leaf, just as it did in the Wheat. 

 The fructification produced on the Barberry, however, is 

 of a totally different kind from any of the forms already 

 described. 



During the spring the Barberry often shows signs of 

 disease, consisting in the appearance of swollen dis- 

 coloured patches on its leaves. When the disease has 

 advanced further we find on the under-side of the leaf, 

 seated upon the swollen place, clusters of exceedingly 

 17 



