PUFFING IN THE DISCOMYCETES 



245 



that is to make its ajipearance when the ascus explodes. Now 



since, as we shall see, each 



operculum is situated so 



that it looks toward the 



opening of the mouth 



of the apothecium, the 



Fig. 1 1 9. — Sarcoscypha protracta. 

 The elements of the liyme- 

 nium. The transverse clotted 

 line indicates the general sur- 

 face of the hymenium as 

 defined by the outer ends of 

 the paraphyses. a, a young 

 and, as yet, non-protuberant 

 ascus showing : a thin cell- 

 wall lined by a thin layer of 

 cytoplasm, a large vacuole 

 filled with cell-sap, and eiglit 

 spores. The wall is slightly 

 thickened at the end of the 

 ascus, and all the eiglit spores 

 are sloped in the same direc- 

 tion, the uppermost being- 

 directed towards the future 

 operculum. b, an older 

 ascus with maximiun pro- 

 tuberancy above the general 

 level of the hymenium ; it 

 is ripe and ready to discharge 

 its spores, c, an exploded 

 ascus which shot out its eight 

 spores and niuch of its cell- 

 sap through an obliquely 

 situated operculate ostiole. 

 The direction of spore-dis- 

 charge, shown by the arrow, 

 was parallel to the vertical 

 axis of the cup. A compari- 

 son of b and c shows that, 

 owing to the elasticity of 

 the cell-wall, the volume of 

 the ascus c, during the ex- 

 plosion, contracted to about 

 one-half, e, some isolated 

 spores shot out from an 

 ascus : their contents include 

 several oil-drops. </, a 

 branched paraplij'sis, with 

 its upper divisions anasto- 

 mosing and densely com- 

 pacted. The dots in the 

 cells represent the red part- 

 icles which make the hy- 

 menium a deep scarlet. The 

 magnification of every part, 

 as shown by the scale, is 26U. 



