FUNGI: MUSHROOMS. 199 



linia. Sometimes they arc united to form a rrust -n-hicli is partly formed 

 from sterile- elements as in Hypoxylon, or they form black clavate or 

 branched bodies as in X}'laria. The black knot of the plum and cherry is 

 also an example. 



The lichens are mostly ascomycctes like the black fungi or cup fungi, 

 while a few arc basidiomycetes. 



417. The morels (Morchella). — There are several species of morels 

 which are common in early spjring on damp ground. Either one of the 

 species is suitable for use if it is desired to include this in the study. Fig. 

 2310, illustrates the Morchella esculenta. The stem is cyhndrical and 

 stout. The fruiting portion forms the "head," and it is deeply pitted. 

 The entire pitted surface is covered In' the asci, which are cylindrical and 

 eight S])ored. A thin section may lie made of a portion for study, or a 

 small piece may be crushed under the cover glass. 



418. The cup fungi. — These fungi are common on damp ground or on 

 rotting logs in the summer. The)' may be preser\'cd in 70 per cent alcohol 

 for study. IManv of them are slia]>ed like broad open cups or saucers. 

 The inner surface of the cup is the fruiting surface, and is covered with the 

 cylindrical asci, which stand side by side. .-V bit of the cup may be sec- 

 tioned or crushed under a co\'er glass for study. 



Mushrooms (Basidiomycetes). 



419. The large group of fungi to which the mushroom belongs is called 

 the basidiomycetes because in all of them a structure resembHng a club, 

 or basidium, is present, and bears a limited number of spores, usuaUy four, 

 though in some genera the number is ^'ariable. Some place the rusts 

 (UredinCEe) in the same series (basidium series), because of the short pro- 

 Mycelium and four sporidia developed from each cell of the teleutospore. 



420. The gill-bearing fungi (Agaricacese). — A good example 

 for this study is the common mu.shroom (Agaricus campestris). 



This occurs from July to Xo\'cml)er in lawns and grassy fields. 

 The plant is somewhat urnbrella-.shaped, as shoAvn in fig. 232, 

 and possesses a cvhndrical stem attached to the under side of the 

 convex cap or pileus. On the under side of the pileus are thin 

 radiating plates, shaped somewhat like a knife Idade. These are 

 the gills, or lamelke, and toward the stem they are rounded on 

 the lower angle and are not attached to the stem. The longer 

 ones extend from near the stem to the margin of the pileus, and 

 the V-shaped spaces between them are occupied by successively 



