274 



FUNGI 



1 1 



under the cap — are usually the most easily obtained. 

 Gather a specimen of some of these according to the 

 directions given above, and examine them as soon as 

 possible, since they decay very quickly. 



388. The Mycelium. — Examine sortie of the white 

 fibrous substance usually called spawn, through a lens. 

 Notice that it is made up of fine white 

 threads interlacing with each other, 

 and often forming webby mats that 

 ramify to a considerable distance 

 through the substratum of rotten wood 

 or other material upon which the 

 fungus grows. These threads are 

 called hyphcB, and are apt to be mis- 

 taken for roots, but they are really 

 the thallus or true vegetative body 

 of the plant, the part rising above 

 ground and usually regarded as the 

 mushroom, being only the fruit, or 

 reproductive organ. The thallus of 

 all fungi is called a mycelmm from 

 mycetes, a Greek word meaning fungi. 



525. — Mycelium of a 

 mushroom {^Agaricns cam- 

 pestris) with young buttons 

 (fruiting organs) in differ- 

 ent stages : i, 2, 3, 4, 5, sec- 

 tions of fructification at 

 successive periods of devel- 

 opment ; m, mycelium ; j/, 

 stipe; /, pileus; /, gill, or 

 lamina ; v, veil. 



389. The Button. — Look on the 

 mycelium for one of the small round 

 bodies called buttons (Fig. 525). These are the beginning 

 of the fruiting body, popularly known as the mushroom, 

 and are of various sizes, some of the youngest being 

 barely visible to the naked eye. After a time they begin 

 to elongate and make their way out of the substratum. 



390. The Veil and Volva. — Make a vertical section 

 through the center of one of the larger buttons after it is 

 well above ground, and sketclf. Notice whether it is en- 

 tirely enveloped from root to cap in a covering membrane — 

 the volva (Fig. 526, a) — or whether the enveloping mem- 

 brane extends only from the upper part of the stem to the 

 margin of the cap — the veil (Fig. 526, d); whether it has 



