THE MYXOMYCETES 



283 



may remain alive for as long as three years. The 

 external appearance of the sclerotium of our type is that 

 of a dry, horny, irregular mass, of a brick-red colour. 

 When moistened, it revives, the walls of the cysts become 

 absorbed, and the contents reunite and recommence the 

 movements characteristic of active life. 



2. THE SPORANGIA AND SPORES 



When a Myxomycete fructifies it completely changes 

 its appearance. The whole of the active protoplasm is 

 used up to form a sorus of sporangia in which the 

 spores are contained. In Fig. Ill 

 a cluster of sporangia (from an allied 

 genus) is shown. The ripe sporan- 

 gium is a rounded hollow case, borne 

 on a stalk ; it has a firm external 

 wall, and its interior is traversed 

 by a network of threads, among 

 which lime is deposited (see Fig. 

 Ill, 6). In the meshes of the net- 

 work are contained the numerous 



FIG. 111. Leocarpus 

 vernicosus. a, group 

 of sporangia on a frag- 

 ment of dead leaf. 

 Magnified 2J. Z>, 

 portion of capillitium 

 with spores. Magni- 

 fied 120. (From Lis- 

 ter's Monograph of the 

 Mycetozoa.) 



spores. 



When fructification is about to 

 take place, the protoplasm accumu- 

 lates at certain points, corresponding 

 to the position of future sporangia. 

 At each of these points the protoplasm heaps itself up to 

 form a projecting mass ; a portion of this hardens and 

 becomes the stalk, while the living part continues to creep 

 upwards, and constitutes the sporangium itself at the top. 

 The outer layer of the terminal mass of protoplasm forms 

 itself into the firm outer wall, while the interior part 



