INTRODUCTION 



I. ORDER HYMENOMYCETES. 



Mycelium floccose, giving rise at once to a distinct hymenium 

 or producing a variously shaped naked or volvate receptacle, 

 even or bearing on its upper or under surface various folds, 

 plates, prickles, etc., clothed with fertile hymenial cells. 



Under the order defined as above by Mr. Berkeley, botanists 

 have described a large number of fungi, including species of re- 

 markable diversity of size, form and appearance. The group 

 contains nearly all of the plants commonly known as mushrooms, 

 club-fungi, coral-fungi and bracket -fungi. In one character the 

 species all agree. Their spores, asexually produced, are borne 

 free on the apices of minute spicules projecting from the surface 

 of the hymenium. 



The life-history of the members of the group is comparatively 

 simple. A spore, falling upon a medium suitable for its develop- 

 ment, under proper conditions of temperature and moisture, soon 

 puts forth slender, thread-like filaments called hyphae, which as 

 growth proceeds at length form a tangled network of fibers, 

 known as mycelium. After a time, if the conditions for growth 

 continue favorable, little rounded nodules or elevations appear 

 at various points upon the plexus of mycelium. These are the 

 beginnings of the fructification or sporophore. As the nodules 

 increase in size they take on definite shapes, and when fully 

 grown develop upon some part of their surface a hymenium, upon 

 which is borne a crop of spores, completing the round of the 

 plant's existence. 



The mycelium is made up of long, branched, multicellula.i 

 hyphae. Fusion of cells, both with other cells of the same hypha 

 and with those of adjacent hyphae is common. By the multi- 

 plexity of these unions and continued growth of the hyphal 

 strands, the mycelium which in its earlier stages consisted of 

 thin, radiating, spider-web filaments, may come to form dense, 

 felted masses. It is usually colorless or white, becoming sordid 

 with age, but may be creamy-white, tan, brown, or even black. 

 In many species it is perennial, and may continue to grow for 

 years without fruiting. Except in cases where it exhibits a dis- 

 tinctive color, it is of little importance in the determination of 

 species. Indeed, where a number of kinds are growing within 

 or upon the same matrix, it is often impossible to distinguish 

 one from another. 



The spores are minute bits of protoplasm, of various sizes, 

 shapes and colors. In one group, the Agaricaceae, they have 

 been made a basis for classification. The colors range from white, 

 through creamy-white to yellow, pale-pink to deep flesh-color. 



