THE FUNGI 271 



forming a little oval tubercle. At first the Mushroom is 

 all stalk ; soon, however, the pileus begins to appear at 

 the top. In the earlier stages there is no separation 

 between pileus and stipe (Fig. 107, B, C). The gills 

 are developed endogenously, while enclosed on all sides 

 by continuous tissue (Fig. 107, D). Later on the pileus 

 begins to spread out laterally (Fig. 107, E), but its 

 under-side is still closed in. The tissue which connects 

 the edge of the pileus with the stalk, and thus encloses 

 the gills from below, is called the velum or veil (Fig. 107, 

 F). At last this becomes ruptured as the pileus ex- 

 pands, and its torn remains adhere to the stipe, forming 

 the ring, which we mentioned in describing the ripe 

 fructification. 



In the case of the Mushroom itself no other form of 

 spore than the basidiospores has so far been discovered. 

 In some nearly allied Fungi, however, additional forms 

 of fructification, such as chains of conidia, are produced 

 on the mycelium. In no case is there any evidence for 

 the occurrence of a sexual process at any stage in the 

 development of Basidiomycetes, unless, indeed, the fusion 

 of nuclei in the basidiuni is an indication of sexuality. 

 The Mushroom itself is a saprophyte, growing in richly 

 manured soil, but some of its near relations are parasitic 

 on trees, to which they do great damage. 



We have now finished our series of types of Fungi. 

 It has only been possible to consider a very few re- 

 presentatives, and many important groups have been left 

 altogether untouched. We have gained, however, some 

 slight idea of the great range of structure which the 

 class presents, and in our later types we have seen how 

 very far the higher Fungi have diverged from the primi- 

 tive algoid forms with which we started our survey. 



