22 BRITISH FUNGI 



The spores or reproducti\-e bodies in fungi, which are analogous 

 with seeds in flowering })lants, are produced on the gills. The entire 

 surface of each side of a gill is covered by specialized cells, which 

 collecti\-ely form the hymenium or spore-bearing surface. This 

 can only be studied in detail when a very thin section of a gill is 

 examined under the microscope, with a magnifying power of at 

 least three hundred diameters. If such conditions are available, the 

 middle portion of the section will be seen to consist of a mass of 

 liyphai running more or less parallel to each other, with numerous 

 free ends curving outwards towards tlie surface of the gill, and 

 ending at the surface of the gill in the various structures collectively 

 constituting the h^-menium. Fig. i6 (Plate B) shows all the various 

 elements met with in the hymenium. The most essential are, a, a 

 basidimn (plural basidia), bearing the spores at its tip or apex. Inter- 

 mixed with the basidia are numerous sterile, club-shaped cells, c, 

 called parcipJiyses. In \-ery many species of fungi basidia and 

 parapliyses are tlie only organs present in the hymenium, whereas in 

 the lumenium of other fungi, a third organ, consisting of large cells, 

 projecting considerably above the general surface of the hymenium, 

 are present, and are termed cystidia. These last-named structures 

 are of great value in determining both genera and species, and it 

 is a good rule to cut a section of the hymenium of every fungus 

 examined for the purpose of determining their presence or absence. 



Sporophore 



In some books the term sporophore is used. It means that 

 portion of the fungus immediately bearing the hymenium. In an 

 agaric, therefore, it would be the cap, from which the gills or 

 liymenium-bearing surface springs. " Hymenophore distinct from 

 the fleshy stem," means that the apex of the stem fits into the 

 flesh of the cap somewhat like a socket ; in other words, there is 

 more or less of a line of demarcation where the flesh of the stem 

 joins the flesh of the cap, although the two are grown together. 

 When no such differentiation between the flesh of cap and stem is 

 present, the " hymenophore is confluent with the flesh of the stem." 

 These terms have been used as a basis for generic distinction, but 

 are in reality valueless, as they are by no means constant. The 

 differentiation between flesh of cap and stem is best seen in the 

 Parasol mushroom [Lcpiota procera), and this feature is sometimes 

 given as one of the characters of the genus, but in many species 

 this feature is absent, in fact, it is not obvious in more than about 

 twenty British agarics. 



Stem 



Most of the terms used in describing the stem, as cylindrical, 

 fnsiforyn, or spindle-shaped, are readily understood. As a rule the 

 stem ends somewhat abruptly at the base ; in some species, however. 



