ORGANS OF REPRODUCTION. 



387 



times again the hymenium lines a number of tubes, as in Poly- 

 porus and Boletus, or a series of solid columns, as in Hydnum, 

 instead of being composed of vertical radiating plates. At other 

 times, the hymenium, instead of exposing its sporiferous mem- 

 brane to the air, as in Agaricus, &c., is enclosed in a leathery- 

 membrane called the peridium, as in Lycoperdon. The former 

 are called Hymenomycetous Fungi; the latter Gasteromycetous 

 Fungi. 



On tlie surface of certain cells of the hymenium which are 

 called basidia {fig. 825, has), the spores are situated. Each 

 basidium commonly bears four spores, spo, a and b, 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 basidia. Among the basidia- of the Agarics 

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

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



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

 liar cells or basidia, have been called Basidiospoi-ous or Acro- 

 sporous ; while those in which the spores are enclosed in thecee 

 or sacs, are termed Thecasporous or Ascosporous ; this differ- 

 ence 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 

 different periods of their growth, and hence such a division 

 must be abandoned. All the so-called Thecasporous Fungi 

 were included by Schleiden under the class of Lichens. 



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- 150), Ascophora, &c., the spores or 



sporules are arranged in great num- 

 bers without any definite order, in a 

 roundish sac called the theca or ascus. 

 Sec, placed at the end of a filament 

 which arises from the mycelium. In 

 the Peziza {fig. 826) and some other 

 Fungi, the theca, t, which are more or 

 less elongated in form, are arranged 

 in groups in a definite order, and com- 

 monly mixed with paraphyses, p. Each 

 theca in the latter Fungi contains four, 

 six, or eight spores or sporules, (or, 

 as they have been also termed, spori' 

 dia,) placed one above the other (fig. 

 826, sp). 



But very little is known of the sper- 



matia of Fungi {fig. 827, s). They 



were discovered by Tulasne, and are 



supposed to be analogous to the sper- 



C G 2 



Fig. 826. 



Fig. 826. Vertical section of the 

 fructification of a Thecaspo- 

 rous Fungus iPeziza). c. Cel- 

 lular substance from which the 

 thecae, t, arise, each of which 

 contains spores or sporidia, sp. 

 V. Paraphyses. 



