450 



A TEXTBOOK OF BOTANY 



[Ch. X 



Order 1. Discomycetes: the Cup Fungi. These are 

 mostly saprophytes, which have an extensive, loose mycelium 



in decaying 

 wood, leaf 

 mold, or 

 rich humus, 

 and bear 

 on the sur- 

 face of the 

 ground a characteristic cup- 

 shaped, and often brightly 

 colored, apothecium, which 

 may reach to three inches in 

 diameter. Some 3000 species 

 are known, though none have 

 direct economic importance. 

 A typical form is a Peziza 

 frequent in forests (Fig. 312). 

 The mycelium is invisible in 

 the ground, but the bright 

 scarlet cup, 2 or 3 inches 



Fig. 312. —Peziza aurantiaca (?). across, is Conspicuous On the 

 Right, a complete cup, with the myce- . 



Hum entangling a shoot of moss; X 2. SUrlaCC ihe bottom ol this 

 Left, vertical section of hymenium, cup J s composed of a HYME- 

 showing asci with ascospores, and . . (( . „ 



intermingled paraphyses, merging be- NIUM, that IS, Ol a tlSSUe 



low into the "tissue" composed of f closely-packed, parallel, 



intertwined mycelial threads ; X 200. . . . 11,1 1 



sterile, hyphal threads, 

 amongst which occur the asci containing each eight spores. 

 The ripe ascospores are expelled by rupture of the ascus and 

 swelling of its contents ; and they are disseminated by wind. 

 In this genus the apothecium, which is an ascocarp, forms 

 without any known fertilization, but in the related Pyronema, 

 it develops as result of the regular fertilization of an asco- 

 gonium through a trichogyne by a sperm-cell (Fig. 313), in 

 the way already described as typical, and apparently in strict 

 homology with the method in Nemalion and other Red Algae. 



