FUNGI. INTRODUCTORY 



411 



a probable origin from organisms like the Red Algae : for they have 

 a female carpogonium with trichogyne. But in many of them such 

 organs of sex have not been found, and there is reason to believe 

 that they are no longer sexually produced. They are divided into 

 two sub-classes, according to the method of production of their 

 spores. Tn the first the spores, commonly eight in number, are pro- 

 duced internally within a closed body, the ascus. These are called 



FIG. 346. FIG. 347. 



Portion of the hymenium of the Morel Honey Agaric (Armillaria mellea). A, 



(Morchella esculenta). a=asci, each con- young basidium with two primary nuclei, 



taining eight ascospores. =paraphyses. B, after fusion of the two nuclei. C=a 



sA=subhymenial tissue. ( x 240.) (After basidium of Hypholoma appendiculalum 



Strasburger.) before the four nuclei derived from the 



secondary nucleus of the basidium have 

 passed into the four basidiospores. 

 D= passage of a nucleus into the basidio- 

 spore. (After Ruhland.) (From Stras- 

 burger.) 



asco-spores, and the sub-class the Ascomycetes (Fig. 346). To them 

 belong many Moulds, Ergot of Rye, the edible Truffle, etc. Examples 

 will be described in Chapter XXVIII. 



In the second sub-class the spores are produced externally, 

 commonly to the number of four, upon^a body called a basidium. 

 They are called basidiospores, and the sub -class the Basidio-mycetes 

 (Fig. 347). To them belong the Mushrooms and Puff-balls ; also the 

 large series of parasitic Rusts, which being more primitive in their 

 characters than the rest, give probable clues to the origin of the 

 Basidiomycetes. They will be described in Chapter XXIX. 



