THE INAEQUI-HYMENIIFERAE 121 



mately one and the same time. There is nothing exactly corre- 

 sponding to this among the Aequi-hymeniiferous Sub-types. Thus, 

 in the Panaeolus Sub-type, the generations of basidia on any one 

 small area of the hymenium are about ten in number, and one 

 generation of basidia does not begin to develop its spores until the 

 previous one has discharged its spores. The nearest parallel among 

 the Aequi-hymeniiferae is to be found in the Psathyrella Sub-type, 

 for there the number of generations of basidia is limited to four and 

 there is overlapping in the development of the successive generations. 

 However, the spores on adjacent basidia of the four generations do 

 not all come to be ripe and ready for discharge at approximately 

 the same time, but ripen and are discharged during four successive, 

 although somewhat overlapping, periods of time, 



(3) The basidia, as a rule, are dimorphic. They are never mono- 

 morphic, although they are occasionally trimorphic and very rarely 

 tetramorphic. In the hymenium of most species of Coprinus, where 

 the basidia are dimorphic, the first-generation basidia are much 

 longer than those of the second generation. The occasional poly- 

 morphism of the basidia, which occurs in a few species only, finds 

 its parallel in the tetramorphism of the basidia of the Psathyrella 

 Sub-type of the Aequi-hymeniiferae. Basidial dimorphism, so far 

 as I know at present, is confined to the Coprini, If, therefore, on 

 examining the hymenium of a strange fungus in face view with the 

 microscope, one perceives that the spores are black and the basidia 

 dimorphic, one has very strong prima facie evidence that the fungus 

 is a Coprinus, 



(4) The basidia of the two generations are interspersed among 

 one another throughout the hymenium and are crowded together, 

 so that frequently spores of the first-generation basidia stand in 

 part vertically above spores of the second-generation basidia. This 

 phenomenon is not limited to the Coprini, for, as we have seen, it 

 occurs also in the Psathyrella Sub-type, We made its acquaint- 

 ance in connection with the descriptions of Psathyrella disseminata 

 and Lepiota cepaestipes. 



(5) While, broadly speaking, the basidia develop their spores in 

 succession from below upwards on each gill and shed their spores 

 in succession from below upwards on each gill, or while, in other 



