366 



THALLOPHYTES 



other agents. When located on favorable organic matter, the 

 spores grow directly into new mycelia. 



Although Morels spring up quickly, often apparently over 

 night, much time is required for the development of the sub- 

 terranean mycelium before the aerial portion' is developed. No 

 sexual reproduction has been discovered 

 in the Morels, and the only spore known 

 is the ascospore. 



Some other edible Ascomycetes, which 

 command high prices in Europe, are the 

 Truffles, which belong in the order Tube- 

 rales. The distinctive feature of the 

 Truffles is that the ascocarp occurs 

 wholly underground. The ascocarp, 

 which is tuber-like, is closed except 

 for a small opening and the spores are 

 released by the decay of its walls. Since 

 they are underground, they are very 

 difficult to find, and experts hunt them 

 by the aid of trained pigs or dogs which 

 detect them through the sense of smell. 

 No sexual reproduction has been dis- 

 covered, but not much is known of their 

 life cycle. 



Cup Fungi (Pezizales). The Cup 

 Fungi include many species most of 

 which are saprophytes. The loose my- 

 celium develops in decaying rich humus, decaying wood, or leaf 

 mold, and when well established it produces above the surface an 

 ascocarp which has the form of a disk, funnel, or cup. Such an 

 ascocarp is called an apothecium to distinguish it from other types 

 of ascocarps. ' 



Peziza. This genus, a species of which is shown in Figure 

 817 j is common in the woods and the cup-shaped apothecium is 

 sometimes 2 or 3 inches across and often brightly colored. In 

 one common form the interior of the cup is bright scarlet. The 

 interior of the apothecium is lined with a hymenium consisting 

 of parallel, sterile, hyphal threads or paraphyses among which 

 occur the asci each containing eight spores. By the swelling and 

 rupturing of the asci the ripe spores are expelled and then scat- 



FIG. 316. Asci (a) of 

 the Morel, showing the 

 ascospores ( X about 200) . 

 The hypha (p) producing 

 no spores is called a pa- 

 raphysis. 



