7 2 



MOKI'IIOLOCY 



Fig. 175. — Peziza: ascocarps (apo- 

 thecia) arising from the mycelium, and 

 lined with the hymenium. 



other forms of ascocarp. The group is also often called the Discomy- 

 cctcs, on account of this characteristic apothecium. In some of the 

 forms sex organs have been discovered, and the ascocarp follows from 

 the sexual act; in others the ascocarp 

 may perhaps arise vegetatively, or at 

 least from no apparent sex organs. 

 Some familiar forms of Pezizales are 

 as follows: 



Peziza. — This genus is conspicuous 

 on account of the brightly lined cups 

 (ascocarps) that arise from the my- 

 celium in decaying wood, humous soil, etc., one of the most common 

 forming a cup with scarlet lining (fig. 175). In the development of 

 the ascocarp, fertile branches (oncogenous 

 hyphae) arise and give rise to asci ; sterile 

 branches intermixed with these give rise to 

 paraphyses (fig. 176); while other investing 

 sterile branches form the cup. The origin of 

 these structures and their probable relation to 

 the act of fertilization is suggested by the fol- 

 lowing investigated forms: 



Pyronema. — In this genus well-developed 

 sex organs have been found (fig. 177). The 

 female sexual apparatus superficially resembles 

 the procarp of Nemalion (see p. 56) in con- 

 sisting of a globular cell (oogonium) and an 

 elongated, tubelike cell (trichogyne or con- 

 jugating tube). The antheridium is a terminal, 

 more or less club-shaped cell which comes into 

 contact with the tip of the conjugating tube and 

 fuses with it. The contents of the antheridium 

 pass into the conjugating tube, whose basal 

 wall is then rosorbed, and the antheridial 

 material passes on into the oogonium (fig. 177). 

 Both antheridia and oogonia are multinucleate, 

 so that fertilization consists of multinucleate 

 pairing (see under Albugo, p. 66). The fer- 

 tilized oogonium is cut off from the conjugating 

 tube again by a wall, and gives rise to branch- 



Fig. 176. — Peziza: frag- 

 ment of a section through the 

 hymenium, showing three 

 asci, each containing eight 

 asccspores, and the hair- 

 like paraphyses. — After 

 Chamberlain. 



