314 



RESEARCHES ON FUNGI 



one generation over the hymenium is economical, in that the 

 basidia are crowded as closely as is consistent with the conservation 

 of that mechanical freedom which is required for the proper 

 development and discharge of the spores. 



Exceptions to the rule just given certainly occur. One some- 

 times finds that, here and there on the hymenium, a few of the 

 basidia are more closely crowded than they are in the areas repre- 

 sented in Figs. 89 and 90. Occasionally, 

 two spores, one belonging to one basidium 

 and the other to another, are so close to 

 one another that they almost touch (Fig. 

 112, F, p. 323). In some rare instances 

 even, actual contact may be observed 

 (Fig. 112, D}. Sometimes also it happens 

 that here and there the basidia are dis- 

 tinctly more loosely scattered than is 

 necessary for the safety of the spores. 

 That such imperfections in distribution 

 FIG. 105. Psalliota cam- should sometimes make themselves mani- 



pestris (cultivated), a, f . . 



a normal disterigmatic fest 1S not to be wondered at, when one 

 basidium; b , a young re fl e cts that a single fruit-body of Panaeolus 



monosterigmatic basi- 

 dium; c, a mature mono- campanulatus may in the course of its 



sterigmatic basidium; d -. -, -~ ,.,-, 



development produce some 50,000,000 



is a seen from abovi 

 e is c seen from above. 

 The spore of c is about 

 twice the volume of one 

 of the spores of a. 

 Magnification, 1,060. 



basidia. 



The Position of the Sterigmata in the 

 Hymenomycetes generally and in Panaeolus 

 campanulatus. First let us consider the 



position of the sterigmata on a single basidium in the Hymeno- 

 mycetes generally. In the vast majority of species the number 

 of sterigmata on the end of each basidium is normally four. How- 

 ever, there are some species in which the basidium has only one 

 sterigma, others in which it has two sterigmata, others in which 

 it has three, others in which it has six, and yet others in which 

 it has eight. Further, in a species in which the number of sterig- 

 mata is normally four, occasionally one may find basidia with 

 three or five sterigmata ; and, where the number is normally two, 

 monosterigmatic basidia are usually frequently present. Probably 



