264 APPLIED BIOLOGY 



and yet are made up of hyphse and have other character- 

 istics showing relationship to molds. 



The term mushroom is here used as a general term includ- 

 ing all forms popularly known as mushrooms and toad- 

 stools, for there is no scientific distinction between them. 

 Formerly all edible fungi were called mushrooms, and all 

 others toadstools; but many so-called toadstools are now 

 known to be edible. Practically and scientifically, then, the 

 two words are now used quite synonymously. 



Structure of a Mushroom. (L) Any common mushroom or 

 toadstool will serve for this study. Specimens may be collected 

 when available and preserved in 5 per cent formalin-solution. Attempt 

 to identify the points of structure described below, and make sketches 

 in note-book. 



Examine a well-expanded specimen. Above ground it consists 

 of a stalk and a cap. On the under side of the cap in most species are 

 the gills, delicate plates radiating from the center. In some species 

 there are numerous holes instead of the gills, and in others there are 

 projections in the form of spines. If the cap be cut from the stalk 

 and left for a few days with gills downward on a sheet of white paper, 

 numerous dark-colored bodies (spores) will fall on the paper, leaving 

 a print of the underside of the cap and showing the arrangement of 

 the gills. Closer examination of the under side of the cap will show 

 the spores on the sides of the gills. 



Below ground the mushroom is attached to thread-like 

 structures which are popularly called the rootlets, but they 

 have no resemblance to real roots of higher plants, except 

 that they are in the soil. These thread-like " rootlets " 

 are hyphce and the entire mass of them is known as a my- 

 celium (see mold, 244). These hyphse branch and grow 

 in the soil, and from time to time new mushrooms or toad- 

 stools grow upward from the mycelium. At first the young 

 mushroom is a small, compact, rounded body, concealed just 

 below the surface until ready for expansion, when it absorbs 

 water rapidly and may reach its full growth in a night. 



Microscopic study shows the stalk and cap to be com- 



