286 RESEARCHES ON FUNGI 



FIG. 96. Panaeolus campanulatus. Semi-diagrammatic vertical section through 

 part of a gill, 0-45 mm. long, showing the arrangements of the elements of 

 the hymenium, subhymenium, and trama. On the left-hand side of the 

 Figure, the section is represented as passing through : a white area of the 

 hymenium, A ; a black area, B ; a brown area, C ; and another white area, 

 D ; and, on the right-hand side, as passing through a black area, E ; a white 

 area, F ; a brown area, G ; and another black area, H. In the white areas, 

 basidia of the present generation are very young, their spores being between 

 and 2 25 hours old and still colourless. In the brown areas, the basidia 

 of the present generation are older, being between 2-25 and 3-75 hours old ; 

 their spores, which are brownish, are in the process of turning black. In the 

 black areas, the basidia of the present generation are the most mature of all, 

 their spores, which have already turned black, being between 3-75 and 7-25 

 hours old. The elements of the hymenium can everywhere be separated 

 into the following five classes : ( 1 ) basidia of the past generations, a, which 

 have discharged their spores and have collapsed ; their ends are concave but 

 look flat in the side view here shown ; (2) basidia of the present generation, b, 

 which are easily recognised because they bear spores ; (3) basidia of the coming 

 generation, c, which are protuberant ; they may or may not have yet developed 

 sterigmata (vide in B, C, and D, the basidia opposite the numbers 4, 5, 6, 7, 

 8, 9, 10, and 11) but have not yet developed spores; (4) basidia of future 

 generations, d ; these are non-protuberant and more or less pear-shaped ; they 

 will bear spores later on ; and (5) the paraphyses, e, sterile elements which 

 never bear sterigmata and spores ; at this stage of the development of the 

 hymenium, they are distinguished from the basidia of future generations by 

 their smaller size, their position between the basidia, their contents, and their 

 tendency to become more or less spherical as they enlarge. 



A wave of development in the hymenium on the left of the Figure is repre- 

 sented as passing from above downwards. The basidia opposite the numbers I, 

 II, III . . . XII, developed their spores in succession. The basidia, I and II, 

 have shed their spores an hour or two ago, and have collapsed. The basidium 

 III has shed its spores about 15 minutes ago and is in the act of collapsing. 

 The basidium IV is about to shed its last two spores ; one, which should be 

 shot away the next second, has a drop of water of full size and about 9 seconds 

 old attached to its hilum. The basidia V, VI, VII . . . XII will all shed their 

 spores in succession. The basidia 1, 2, 3 . . . 11 will develop spores in succession 

 in their numerical order. They are about 8 hours developmentally behind 

 the adjacent basidia I, II, III . . . XII. Thus 1 is eight hours behind I, 5 eight 

 hours behind V, 10 eight hours behind XII, etc. 



Another wave of development is shown as passing upwards through the 

 hymenium on the right-hand side of the Figure. Thus there is a set of basidia I, 

 II, III . . . XI where I is the oldest, II the next oldest, and so on down to XI. 

 Similarly in the series 1, 2, 3 ... 12, 1 is the oldest, 2 the next oldest, and 

 so on down to 12. Here again the series 1, 2, 3 ... 12 is developmentally 

 about 8 hours behind the series I, II, III . . . XII. 



The exact size of every element may be read by using the scale at the base 

 of the Figure. Magnification, 465. 



