5o6 RESEARCHES ON FUNGI 



represented semi-diagrammatically on the same scale in Fig. 204 

 a germinated teleutospore of Puccinia graminis and a portion of 

 the hymenium of Psalliota campestris. On the left side of each 

 drawing is shown a basidium bearing four ripe spores, and on the 

 right side a basidium discharging its spores. The spores shown at 

 a, b, and c in A correspond in their stages, in respect to discharge, 

 to a}, b^, and c^ in B. 



The length of the sterigmata was found to be variable. In some 

 basidia it was about 7 ^ and in others as much as 18 yt^. 



In some of my preparations it was observed that the basidia 

 had grown outwards from their teleutospores in a film of water 

 on the glass slide and, whilst still submerged, had developed at 

 the surface of the film sterigmata and spores, as represented in 

 Fig. 205, A. The sterigmata always developed so that they grew 

 into the air : it therefore seems likely that they are negatively 

 hydrotropic. The spores developing on the ends of the sterigmata 

 were normal in appearance ; and, owing to their fixed position in 

 space, their growth and discharge could be observed without much 

 difficulty. 



The discharge of spores developed from a submerged basidium, 

 such as that represented in Fig. 205, A, was observed several times 

 and was found to differ somewhat from the discharge of spores 

 developed on aerial basidia, such as those represented in Fig. 204. 

 Just as in an aerial basidium, in a submerged basidium a drop of 

 water was excreted from the hilum before the discharge of each 

 spore, but the drop often attained relatively gigantic proportions. 

 A few minutes before discharge took place it was observed that a 

 drop of water began to be excreted from the hilum and quickly 

 attained a size equal to the maximum for spores borne on aerial 

 basidia (Fig. 205, A, a). However, instead of the spore being dis- 

 charged at this stage, the drop continued to grow, and soon it 

 stepped up on to the body of the spore (Fig. 205, A, 6). Further 

 growth took place until the spore became entirely surrounded with 

 a large drop from 10 yu, to 17 yn in diameter. Then, after a delay of 

 several minutes, the spore, surrounded by its drop, was suddenly 

 shot away and became lost to view. In Fig. 205, A, there is shown 

 at c a drop of water enclosing a spore which has just been discharged 



