132 



THE POPULAR SCIENCE MONTHLY. 



a pair of dark-colored spots near the top {see 2 and 3, Fig. 2), 

 which mark the position of the future gills. A little later the cap 

 begins to take shape, the gills develop, and a membrane may be seen 

 stretching from the stem to the edge of the growing cap. As matu- 

 rity approaches, this membrane is ruptured and forms a ring around 

 the stem, as shown in Fig. 8. This membrane is called the veil or 



Fig. 3. Common Meadow Mushboom. 



volva. The parts to be borne in mind, then, are the mycelium or veg- 

 etative portion, and the stem, cap, gills, hymenium, ring, and volva, 

 all of which belong properly to the reproduction of the plant, and all, 

 except the hymenium, may be readily traced in Fig. 3, 



If, when the mushroom is mature, you cut off the stem close to the 

 gills, and place the cap, gills downward, upon a sheet of paper for a 

 few hours, or all night, it will leave behind a likeness of itself in the 

 shape of radiating lines that correspond to the spaces between the 

 pairs of gills. These lines are formed by minute microscopic spores 

 that have been thrown down in profusion from the hymenium, and in 

 greatest number from the opposed surfaces of the gills. In making 

 the experiment with this mushroom use white paper, but for light- 

 spored species black paper should be taken. These little germinal 

 bodies are cellular in structure, and of the extremest minuteness ; 

 thousands of them are required to form a body the size of a pin's- 

 head. Their color is constant, and is used as a means of identifica- 

 tion ; but among the higher plants color is a character that cannot be 

 thus relied upon. The spore is a simple cell, and the entire mushroom 

 is cellular in composition. The delicate threads of the mycelium are 

 foi'med of rows of cells placed end to end, and microscopic inspection 

 of thin slices from the stem and cap show, that they also are composed 

 of cells alone. 



