CRYPTOGAMS 



359 



Pig. 282. — Lachnea pulcherrima. Apothecium ruptured, 

 showing old and young asci between the paraphyses. 

 (After Woronin, from v. Tavel.) 



The apothecia 



of the other species they are gray or brown. Such cup-shaped fructifications are 

 not termed perithecia but apothecia. In their early stages the apothecia are 

 closed, but soon after the rudi- 

 ments of the hymenium are 

 developed, the thin, outer en- 

 velope ruptures and the fructi- 

 fication becomes gynmocarpous 

 (Fig. 282). The hymenium is 

 situated on the inside of the 

 cup. The hypothecium, or that 

 part of the fructification im- 

 mediately beneath the inner 

 hymenial layer, is composed 

 of closely interwoven sterile 

 hyphas. These sterile hyphse 

 give rise to the paraphyses, 

 while the eight -spored asci 

 growing in between the para- 

 physes are produced from 

 special ascogenous hyphee, 

 which sooner or later become 



differentiated as thick branching filaments, in the hypothecium. 

 are gregarious, but each is distinct from the other. 



Sclerotia of varying form are produced by different species of Sclerotinia. In the 

 case of Sclerotinia tuberosa they have the appearance of black tuberous bodies and 

 grow upon the dead, underground rhizomes of Anemone nemorosa. The sclerotia 

 of other species are formed like those of Claviceps, in infected ovaries (e.g. 

 S. haccarum upon Vaccinium Myrtillus). In the 

 spring the sclerotia germinate and give rise to long- 

 stalked apothecia. 



The Phacidiaceae, appearing on leaves or bark, 

 form a special group of Discomycetes. Rhytisma 

 acerinum, common on the leaves of the Maple, 

 belongs to this family. In the course of the summer 

 it forms large black incrustations of pseudo-paren- 

 chyma, from which at first only conidial fructifica- 

 tions arise. In the autumn the rudiments of the 

 apothecia are formed ; they do not develop into 

 mature apothecia until the succeeding spring, when 

 they make their appearance in the form of irregular 

 fissures, with a yellowish hymenium upon the crus- 

 taceous sclerotia, which have remained over winter 

 upon the dead leaves. 



The highest development is exhibited by the 

 peculiar fructifications of the Selmllaceae or Morel 

 Fungi, whose mycelium, like that of the Truffle 

 Fungi, vegetates underground in the humus soil of 

 woods, but produces soft wax-like aerial fructifica- 

 tions. In the genus Morchella, Morel (Fig. 283), the 

 fructifications consist of a thick erect stalk, bearing a club-shaped or more or less 

 spherical cap or pileus, which bears the hymenium, with its eight-spored asci, on 



Fig. 283. — Morchella esculenta. 

 (| nat. size.) 



