464 RESEARCHES ON FUNGI 



campanulatus and applies equally to all other members of the Panaeolus 

 Sub-type. 



The author has studied the hymenium of Panaeolus campanulatus : 



(1) before the development of the spores, (2) in the middle of the spore- 

 fall period, and (3) at the end of the spore-fall period when the hymenium 

 has become exhausted ; and he has illustrated his analyses with a 

 complete series of drawings, showing the hymenium both in surface 

 view and in cross-section and indicating the time and space relations 

 of all the elements. 



The paraphyses of Panaeolus campanulatus, unlike the young basidia, 

 are destined from the first to remain sterile. They are about equal in 

 number to the basidia ; but they differ from the basidia in : (1) size, 



(2) position, (3) form (as they grow older), (4) early vacuolisation and 

 ultimate disappearance of their cytoplasm except for a very thin wall- 

 layer, (5) never developing either sterigmata or spores, and, doubtless, 

 also, (6) in the non-fusion of the tw r o nuclei with which they are at first 

 provided. As, during the spore-fall period, more and more basidia 

 discharge their spores and collapse, the paraphyses swell up and to a 

 large extent fill up the gaps made in the hymenial layer by the shrink- 

 age of the exhausted basidia. In general, the paraphyses appear to 

 act as mechanical supports and nurse-cells for the spore-bearing 

 elements. 



A basidium, about 20 minutes after discharging the last of its four 

 spores, collapses : its convex end bearing the sterigmata sinks down 

 and becomes concave, thus drawing the sterigmata into a concavity. 

 The shaft of the basidium then shrinks laterally and the four sterigmata 

 become melted down to sterigmatic stumps. Exhausted basidia can be 

 recognised in cross-sections by the flat rims of their concave ends and 

 by their shrunken shafts, and in surface view by their lack of contents 

 and by their sterigmatic stumps. 



Irregular waves of hymenial development pass across the mottled 

 surface of each gill. These waves are comparable with the undulations 

 which may be observed in the epithelium w 7 hich produces spermatozoa 

 in the testicular tubules of the Mammalia. 



The wasted spores, i.e. those which are not properly discharged from 

 the sterigmata and which cling to the hymenium, form but a very small 

 percentage of the total number of spores produced. 



The author shows that the protuberancy of the mature basidia, the 

 collapse of the exhausted basidia, the relative positions of spores on 

 individual basidia with 2-8 sterigmata, and the relative positions of 

 the spore-bearing basidia of a single generation are all factors making 

 for the success of the fruit-body as an organ for the production and 

 liberation of the spores. 



Many Hymenomycetes are known in which the basidia are 

 disterigmatic and bisporous ; but Coprinus narcoticus is at present the 



