0EGA2hS of EEPRODrCTIOX. 379 



membrane called the veil or mdusium, but this is soon ruptured 

 by the development of the pileus and stipe, and is either com- 

 pletely torn away from the latter, or, as is more commonly the 

 case, it remains as a sort of ring or annulus, an, surrounding its 

 upper part. 



The recent researches of Professor Oersted upon Agaricv.s 

 variabilis appear to show that the generative process is carried 

 on in the Agarics and allied Fungi, in the mycelium, and that 

 the so-called fructification is analogous to the sporangia or 

 urns of Mosses and the thecfe of Perns, which are the products 

 of sexual union, as already noticed. 



The hymenium varies in its character and position in dif- 

 ferent genera. In some it is on the upper surface of the pileus, 

 as in Helvella, instead of on the lower, as just described, in 

 Agaricus. Sometimes again the hymenium lines a number of 

 tubes, as in Polyporus and Boletus ; or a series of solid columns, 

 as in Hydnum, instead of being composed of vertical radiating 

 plates. At other times, the h}Tnenium, instead of exposing its 

 sporiferous membrane to the air, as in Agaricus, is enclosed 

 in a leathery membrane called the peridium, as in Lycoperdon. 

 The former are called Hymenomycetous Fungi ; the latter Gas- 

 teromycetous Fungi. 



On the surface of certain cells of the hymenium which are 

 called hasidia {fig. 828, has), the spores are situated. Each 

 basidium commonly bears four spores, spo, a, and h, situated on 

 stalks or branches proceeding from it. These stalks have been 

 termed by some sporophores, a name which has been also used 

 as synonymous with hasidia. Among the basidia of the Agarics 

 opaque vesicles occur, which have been termed pollinaria, cysfidia, 

 or utricles. They appear to be paraphyses or abortive basidia. 



All Fungi which thus bear their spores on the outside of pecu- 

 liar cells or basidia, have been called Basidiosporous or Acro- 

 sporous] while those in which the spores are enclosed in thecse 

 or sacs, have been termed Thecasporous or Ascosporous ; this 

 difference was formerly thought to constitute a firm basis for the 

 division of the Fungi, but recent researches have shown that both 

 basidiospores and thecaspores occur in the same species at dif- 

 ferent periods of their growth, and hence such a division must be 

 abandoned. 



We must now briefly allude to the Thecasporous or Ascospo- 

 rous Fungi. The simplest form of these is seen in the Mildews. 

 Thus in Mucor {fig. 4), the spores or sporules are arranged in 

 great numbers without any definite order, in a roundish sac 

 called the theca or asci's, placed at the end of a filament which 

 arises from the myceliiim. In the Piziza {fig. 829) and some 

 other Fungi, the thecae, t, which are more or less elongated in 

 form, are arranged in groups in a definite order, and commonly 

 mixed with paraphyses, p. Each theca in the latter Fungi con- 



