These basides together with a series of elongated cells, termed paia- 

 physes, packed closely together side by side, and intermixed with other 

 sterile cells, called cystidia, coustitute the spore-bearing surface or 

 hymeuium of the plant. 



To the naked eye this hymenium appears simply as a very thin smooth 

 membrane, but when a small portion of it is viewed through a microscope 

 with high powers its complex structure is readily observed and can be 

 carefully studied. 



The tSporldiferoxs fungi are represented by the families Physomycetes 

 and Ascomycetes. The first of these consists wholly of microscopic 

 fungi. 



Ascomycetes. — In the plants of this family the spores are not sup- 

 ported upon basidia, but instead are enclosed in minute sacs or asci 

 formed from the fertile cells of a hymenium. In this connection it would 

 be well to state that Saccardo does not recognize the divisions Sporifera 

 and Sporldifera by those names. 



They are nearly the equivalent of Basidiomycetes and Ascomycetes. 



What Cooke names Physomycetes, Saccardo calls Phycomycetese, intro- 

 ducing it in his work between Gasteromycetete and Myxomycetese, which 

 some mycologists consider somewhat out of place. 



Saccardo calls its asci (sacs which contain the spores) sporangia. He 

 does not regard them as genuine asci, but as corresponding more to the 

 peridium of the Gasteromycetece and Myxoniycetem. 



Peck says that this group seems to present characters of both Hypho- 

 mycetes and Ascomycetes, with a preponderance towards Hyphomycetes. 



It is a small group, however, and since it consists wholly of micro- 

 scopic fungi, need not be farther considered in this work. 



In the Ascomycetes are included the sub-families Discomycetes, Pyre- 

 nomycetes, and Tuberacei. Of these the Discomj^cetes and the Tube- 

 racei are the only groups which contain any of the mushrooms, and but 

 few of these are large enough or sufficiently tender to possess value as 

 esculents. A good example of the first (Discomycetes) is found in the 

 Morel, and of the second (Tuberacei) in the Truflie. 



In the Discomycetes or " disk fungi," the spores are produced in minute 

 membraneous sacs, each sac usually containing eight spores. These 

 spore sacs are imbedded in the flesh of the exterior and upper surface of 

 the mushroom cap. 



In the four classes, Hymenomycetes, Gasteromycetes, Discomycetes, 

 and Tuberacei, therefore, are included all of the plants which are here 

 designated under the generic term of "mushrooms." 



Some idea of the relative numerical value of these classes may be ob- 

 tained from the following figures given by the distinguished British my- 

 cologist, M. C. Cooke : 



" Hymeuomycetete — total number of described species 9,600 



Gasteromycet^— " " " " " 650 



Discomyceteaj— " " " known " 3,500 " 



