COPRINUS AND NON-COPRINUS TYPES 65 



days, whereas in the Coprinus Type all the spores that are to be 

 discharged must be ripe at approximately one and the same time, 

 as they are all ultimately discharged and then the hymenium beneath 

 them is destroyed by autodigestion in the course of a very few 

 minutes. 



In cross-section, the gills of the Non-Coprinus Type are wedge- 

 shaped, whereas those of the Coprinus Type are parallel-sided or 

 subparallel-sided. This fundamental difference is correlated with 

 the fact that, in fruit-bodies with gills of equal depth, the gills of 

 the Non-Coprinus Type are considerably more massive than those 

 of the Coprinus Type. This is illustrated in Fig. 41, where A, B, 

 and C are cross-sections of the gills of Coprinus atramentarius , 

 Collybia platyphylla, and Psalliota campestris respectively, all 

 drawn to the same scale. The gills of the Coprinus and of the 

 Collybia are of the same depth, namely, 12 mm., and inspection 

 shows at once that a single gill of the Collybia is equal in mass to 

 several gills of the Coprinus. ^ In other words, with equal masses 

 of material employed in the production of gills, the fruit-body of 

 the Coprinus Type produces more gills than that of the Non-Coprinus 

 Type. Hence we may conclude that per unit mass of the gills 

 the area of hymenium supported is much greater in the Coprinus 

 Type than in the Non-Coprinus Type. Therefore, if the number of 

 units of area of the hymenium produced per unit of mass of the gills 

 be taken by itself as the criterion for efficiency in fruit-body con- 

 struction, the Coprinus Type may be said to be several times as 

 efficient as the Non-Coprinus Type. 



From the preceding discussion it is obvious that the advantage 

 of the Non-Coprinus Type over the Coprinus Type in the number of 

 spores produced per unit area of the hymenium is counterbalanced 

 by the disadvantage that the gills of the Non-Coprinus Type must 

 of necessity be much more massive than those of the Coprinus 

 Type. 



The pileus-flesh of the Non-Coprinus Type is, as a rule, much 



^ A paper cross-section of a gill of the Coprinus and another of a gill of the 

 Collybia, each twelve times the natural size, were weighed separately against paper 

 squares (each 5 mm. square), and it was found that the cross-sectional area of a 

 gill of the Collybia was approximately seven times as great as the cross-sectional 

 area of a gill of the Coprinus. 



VOL. IV, F 



