SECT. I 



CRYPTOGAMS 



397 



A reduction in sexuality has occurred in many Disconiycetes. Thus Lachnca 

 stercorea develops an ascoj^oniuni as ryrimona does, but with a 5- to 6-celled 

 trichogyne ; an antheridium is still present, but the male nuclei only enter the 

 tricliogyne and are functioidess. They do not reach the ascogonium, the nuclei in 

 which fuse in pairs, after which tlie ascogenous hyphae are formed (''^). In 

 IIuTiiaria granulata no trichogyne is formed and antheridia are completely 

 wanting ; the nuclei of the ascogonium fuse in pairs ("^). Lastly, in Huinaria 

 rutilans no sexual organs are formed, but fusion of nuclei takes place in the complex 

 of hyphae, from which the ascogenous hyphae arise C^''). 



The asci develop in various ways at the ends of ascogenous hyphae. As a rule 

 the end of the ascogenous hyphae when about to form an ascus becomes curved 



Fk.'. 327. — Devplopment of the Ascns. A-C, 

 I'yronema roiifluens. (After Harper.) 

 D, Young ascvis of Boudiera with eight 

 spores. (After Clat^ssen). ExiJlanation 

 ill text. 



Fl(i. 3-2S.—Monhelhi i^^ulenht. 

 (I nat. size.) 



into a hook-like shape (Fig. 327, ^l). The two nuclei of the young ascus {a) lie 

 near to the bend, and on the formation of transverse walls are separated from 

 the uninucleate terminal cell {h) and the stalk-cell (s), which also has a single 

 nucleus. The two nuclei of the young ascus fuse (C), and the resulting nucleus 

 gives rise by repeated division to the nuclei of the eight ascospores {D). 



The highest development is exhibited by the jieculiar fructifications of the 

 Helvellaceae, whose mycelium grows in the humus soil of woods. In the genus 

 Morchella (Fig 328), the fructifications consist of a thick erect stalk, bearing a 

 club-shaped or more or less spherical cap or pileus, which bears the hyraenium, 

 with its eight-spored asci, on the reticulately indented exterior surface (Fig. 317). 

 The Morchellas are edible ('•'), in particular M. csciUcnta and M. conka. The former 

 has a yellowish -brown cap, ovately spherical in shape, and attains a height of 

 12 cm. ; the cap of the latter is conical and dark brown, and it reaches a height of 

 20 cm. Gyromilra esculenta, with dark brown cap and white stalk, and others 

 are also edible. In their external appearance the i'ructifications of these highly 

 developed Discomycetes greatly resemble tlmse of the Basidiomycetes. 



