CRYPTOGAMS 



393 



wood, but sometimes also on humus soil. They produce saucer- or cup-shaped 

 fructifications of a fleshy or leathery consistency, and usually of small dimensions. 

 One of the largest forms, Peziza aurantiaea (Fig. 331), has irregularly bowl-shaped 

 fructifications, which may be seven centimetres broad and of a bright orange-red 

 colour, while in most of the other species they are grey or brown. Such cup- 

 sliaped fructifications are termed APOTHECIA. 



The development of the apothecium may be described for Pyronema confluens, 

 in which it has been thoroughly investigated by R. HARPER. The fruit-body of 

 this species is about 1 mm. across, and of a yellow or reddish colour ; it often 

 occurs on spots where fires have been kindled in woods. The carpogonia are 

 especially large in this species, and several usually take part in the formation of 

 each apothecium (Fig. 333 A). The carpogonium or ascogonium consists of the 



Kir;. 334. Development of the'Ascus. A-C, 

 Pyrone-iYM confluent. (After HARPER.) 

 D, Young ascus of Koudiera with eight 

 spores. ( After CLAUSSEN.) Explanation 

 in text. 



Fiu. 335. Morehella esculenta. 

 (J nat. size.) 



spherical, multinucleate oogonium, on the apex of which a multinucleate curved 

 cell, the trichogyne, is situated. The cylindrical, multinucleate antheridium 

 arises below the oogonium ; its apex comes into open communication with the tip 

 of the trichogyne by the breaking down of the intervening walls. The male nuclei 

 first wander into the trichogyne cell, and then, by the breaking down of the basal 

 wall of the latter, into the oogonium. In the oogonium the male nuclei conjugate 

 in pairs with the numerous female nuclei, while the nuclei of the trichogyne cell 

 disintegrate. The egg-cell then becomes limited from the trichogyne by a new 

 <(!! wall and sends out ascogenous filaments containing the conjugated nuclei. 

 These filaments branch and ultimately terminate in asci (E), while the sterile 

 hyphse and the paraphyses of the fructification are derived from hyphse arising 

 beneath the carpogonium. In Ascobolus, a genus related to Pyronema, the asco- 

 gonium is to begin with multicellular, but all the cells empty their contents into 

 a single large one, from which the ascogenous hyphse then arise. 



The end of the ascogenous hypha ( 60 ) when about to form an ascus becomes 

 curved into a hook-like shape (Fig. 334 A). The two nuclei of the young ascus (a) 

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



