PUFFING IN THE DISCOMYCETES 253 



puffing and therefore corresponding with the radial-longitudinal 

 section shown in Fig. 120, B. In Fig. 121, B, the following points 

 may be observed : (1) the asci have contracted so that their dia- 

 meters are about three-quarters of what they were before spore- 

 discharge took place ; and (2) the openings of the asci (the opercula 

 are not shown) are all obliquely situated on the upper side of the 

 end of each ascus. 



In Fig. 122, which supplements Fig. 121, B, an exhausted 

 hymenium in surface view is shown on a larger scale. In Fig. 122 

 one may again notice : (1) the wide separation of the asci by the 

 paraphyses, and (2) the upper obhque positions of the ascus-aper- 

 tures ; but, in addition, one may observe (3) that the opercula are 

 all hinged in the same manner, i.e. on the side of the openings nearest 

 the bases of the asci. 



Figs. 120, 121, and 122 taken together provide data which allow 

 us to form a clear conception of the spatial relations of the elements 

 of the hymenium to one another and to the cup-shaped apothecium 

 as a whole. 



Correlations and Fruit-body Efficiency. — It is evident that the 

 hymenium is wonderfully well fitted for producing and Hberating 

 spores from an apothecium with a more or less obconical interior. 

 Correlated with this form is the upward-looking opening of each 

 ascus, made when discharge of the spores takes place. If the ascus- 

 openings did not look upwards toward the mouth of the apothecium, 

 but looked sideways or were terminal, the spores could not be ejected 

 efficiently from the apothecial cavity. The upward inchnation of 

 the top spore of each ascus and of the other seven spores in the spore- 

 chain is correlated with the position of the opening that will be formed 

 when the ascus explodes. If the ascospores were inclined down- 

 wards instead of upwards, when an ascus opened the exit of the 

 spores through the opening would be rendered much more difficult 

 if not impossible. 



The area taken up by the paraphyses in the hymenium is some- 

 what greater than that taken up by the asci. Why should there not 

 be fewer paraphyses and more asci ? Would not this make for 

 greater efficiency ? Let us attempt to answer these questions. 

 Firstly, it is to be remarked that paraphyses form an essential part 



