PSALLIOTA CAMPESTRIS 415 



essentials with similar Figures for Panaeolus campanulatus and 

 Stropharia semigtobata, which were actually made with the help 

 of the camera lucida. 



The area of Fig. 146 is approximately equal to one-hundredth 

 of a square mm. The present-generation basidia (those bearing 

 spores) are identical with those shown in the right two- thirds of 

 Fig. 142 (p. 407). The piece of hymenium is supposed to have 

 been shedding spores for about 24 hours, so that already it contains 

 a number of basidia belonging to past generations. However, it 

 is far from exhaustion. Indeed, it should continue to shed spores 

 for at least four days longer. New generations of spores are 

 potentially resident in the coming-generation basidia and in the 

 numerous basidia belonging to future generations. There are no 

 cystidia on the surface of the gills. All the elements belong to 

 one or other of the foUowing five groups : past-generations basidia, 

 a a ; present-generation basidia, b b ; coming-generation basidia, c c ; 

 future-generations basidia, d d ; permanently sterile paraphyses, e e. 



The past-generations basidia, a a, are collapsed and shrunken, 

 devoid of protoplasmic contents, with tops drawn down to the 

 general level of the hymenium. Their free ends are concave and 

 contain the remains of the sterigmata which are reduced to mere 

 stumps. When a mushroom has been shedding spores for five 

 or six days and is in the last stages of hymenial exhaustion, most 

 of the past-generations basidia are found to have entirely disap- 

 peared. No such disappearance of these elements, however, is 

 shown in the present drawing, as the piece of hymenium is supposed 

 to have been shedding spores for not more than 24 hours. 



The present-generation basidia, b b, are distinguished from all 

 others by the fact that they bear spores. The spores on the left- 

 hand side of the Figure are colourless and many of them have 

 not attained full size, while those on the right-hand side are of 

 full size and completely pigmented. Most of the basidia of the 

 present generation are bisporous, b b ; but here and there certain 

 of them are monosporous, m m. The spores on the latter have 

 decidedly larger diameters than those on the former. As soon 

 as a present-generation basidium has shed the last of its spores, 

 it becomes a past-generation basidium : after about twenty 



