DEVELOPMENT OF PLANTS 



2 19 



are broadly open and often associated with large masses of my- 

 celium, thus forming a conspicuous stroma. 



91. Order g. Pezizales or the Cup Fungi. — These plants are 

 characterized by the formation of fleshy, leathery or gelatinous 

 cup-like ascocarps that range in size from mere specks to forms 

 four or five inches in diameter (Fig. 156). The mycelium lives 

 upon the humus in the ground or on decaying plants and ap- 

 parently in this and the next order frequently develops the asco- 

 carps directly without a reproductive process. In Pyronema, 

 however, Harper has shown that reproductive organs are formed 

 that are more suggestive of those of the red algae than was the 

 case in the blue moulds and downy mildews previously noted. 

 The female gametangium has a long tubular outgrowth that 

 curves over and becomes closely applied to the male (Fig. 157, 



Fig. 157. Sexual reproduction of one of the cup fungi, Pyronema: A, 

 the flask-shaped female gametangium, 0, is seen in various stages of fusion 

 with the male gametangium, an. B, the gametospores, g, germinating and 

 forming branching hyphae which bear the asci, as. These asci are asso- 

 ciated with hyphae or paraphyses, p, that arise from the mycelium. The 

 asci and paraphyses constitute the hymenium. — After Harper. 



A). The dissolution of the separating walls permits the fusion 

 of the gametes, after which, the gametospore develops a number 

 of erect sac-like hyphae or asci (Fig. 157, B) . Adjoining hy- 

 phae of the mycelium grow up among the asci and around them. 



