PANAEOLUS CAMPANULATUS 317 



micans Fr., 1 P. sagittaeformis Pat., 2 P. Helenae Pat., 3 Clavaria 

 cinerea Fr., 4 Hygrophorus agathosmus, 5 Pholiota logicians, 6 Tubaria 

 conspersa, 7 and Corticium commixtum v. H. et L. 8 When the 

 whole number of Hymenomycetes is considered, the species with 

 disterigmatic basidia are relatively few. However, these exceptional 

 species are scattered through a considerable number of genera 

 from the highest to the lowest. Possibly, when a sufficient number 

 of critical studies has been made, it will be found that almost 

 every large genus of the Hymenomycetes has one or more 

 species which normally have disterigmatic basidia. In Amanita 

 bisporigera, Coprinus bisporus, and Psattiota campestris, there can be 

 but little doubt that the two-spored condition has been obtained 

 by reduction from the four-spored, and possibly this is true in all 

 disterigmatic species. The suppression of two sterigmata out of 

 four may be likened to the suppression of spines in the Prickly 

 Opuntia and the suppression of colours in certain flowers. 

 Evolution seems to have taken place by means of the loss of a 

 character. 



In disterigmatic basidia the two sterigmata are always set 

 opposite to one another in a symmetrical manner, one on each 

 side of the top of the basidium-body. At their origin, they seem 

 to repel one another and thus come to be situated as far apart as 

 possible (Fig. 105; also Figs. 146 and 147, pp. 416, 429). 



Tristerigmatic basidia, so far as I know, are the rule for one 

 species only. I have discovered that in Coprinus narcoticus 

 (Fig. 108), the normal number of sterigmata for each basidium 

 is three only. Mixed with the tristerigmatic basidia, however, 

 are a certain number of tetrasterigmatic. The fruit-bodies used 

 for my observations came up spontaneously in 1912 and again 

 in 1922 in laboratory cultures of horse dung collected from the 

 streets of Winnipeg. The species was readily recognisable from 

 the first by the remarkably pungent odour of the pileus during 

 autodigestion. A photograph of the hymeiiium seen from above 



i, 2. 3, 4 jj. Patouillard, Tabulae analyticae fmigorum, s6r. 1, 1883-1886. 



5. 6, 7 y F a y 0( j 5 "Prodrome d'une histoire naturelle des Agaricines," Ann. 

 sci. nat., 1 ser., T. IX., 1889, p. 262. 



8 F. von Hohnel und V. Litschauer, " Beitrage zur Kenntnis der Corticieen/' 

 Sitzungsb. der K. Akad. der Wiss. in Wien, Bd. CXVI, 1907, p. 83. 



