COPRINUS STERQUILINUS 



189 



Coprinus sterquilinus is a typical member of the Comatus Sub- 

 type. 



The identity in general form shown by the gills of Coprinus 

 sterquilinus and C. comatus may be realised at a glance by comparing 

 Figs. 78 and 79 in tliis 

 volume with Plate II, 

 Fig. 5 and Plate III, 

 Fig. 14 in Volume I, 



The significance of 

 the flanged condition of 

 the gills is the same for 

 Coprinus sterquilinus as 

 for C. comatus, and is 

 to be sought in the 

 nature of the special 

 arrangements provided 

 for the free development 

 of the basidia on the 

 surfaces of opposing 

 gills. Opposing spore- 

 bearing basidia, such as 

 those shown in Fig. 79, 

 must not come into con- 

 tact with one anothei or 

 there would be mutual 

 mechanical interference 

 during the production 

 of the spores. Now 

 in Coprinus sterquilinus there are no cystidia on the sides of the 

 gills. In Coprinus atramentarius, the cystidia which stretch between 

 adjacent gills act as stays or distance-pieces and serve to keep the 

 surfaces of adjacent gills, which are very thin and weak, at such 

 a distance apart as is necessary for the free development of the 

 basidia.^ In the absence of cystidia, the necessary interlamellar 



1 A. H. R. Buller, " The Function and Fate of the Cystidia of Coprinus atra- 

 mentarius, etc.," Annals of Botany, vol. xxiv, 1910, pp. 613-628. Also vide infra, 

 chap. ix. 



Fig. 78. — Coprinus sterquilinus. A, part of a 

 transverse section of a pileus at a stage like 

 that represented in Fig. 71. The hollow stipe 

 and seven gills are shown. Between each pair 

 of adjacent gills there is an interlamellar space. 

 Each gill has a swollen edge or flange close to 

 the stipe. B, one of the gills enlarged showing 

 the flange formed by the swollen gill-edge. 

 Magnification : of A, 10 ; of B, 20. 



