HEART-ROT 103 
have occasionally been found. Each spore is attached to 
the basidium by a very thin extension of the latter called 
a sterigma (fig. 41, B, st.), and when ripe the spore which. 
develops at its extremity is cut off from the sterigma by 
a transverse septum. The mature spores are hyaline, 
measure 5-5-7 X 4-5-5, and have a slight projection at one 
side, where they are attached to the sterigmata. The 
Fic. 42.—Diagrain showing the necessity for the pores tu be vertical. 
In a, in which the orientation is correct, all the spores escape. In B, 
which is tilted, only a small proportion of the spores escape from the 
pores and the rest stick to the sides. For the sake of clearness the pores 
are shown as much wider in proportion to their length than is the case 
in Fomus annosus. For correct proportions the pores should be eight 
times as long as in the diagram. The loss of spores through tilting would 
then be much greater than that shown in the diagram. 
paraphyses are similar to the basidia in shape, but remain 
sterile, and scrve to keep the basidia at appropriate 
distances. 
The spores, like those of most Hymenomycetes, arc 
slightly sticky, so that if they come in contact, during their 
fall, with the sides of the pores, they adhere and fail to 
escape. To prevent this it is necessary for the pores to be 
exactly vertical, and the fungus, by some means not as yet 
understood, has the power of making them grow in the 
