154 RESEARCHES ON FUNGI 



such distances apart that the spores of adjacent basidia cannot touch 

 one another, (2) that the spores of the long basidia are raised so far 

 above the spores of the short basidia that the spores of one generation 

 cannot touch those of the other generation, and (3) that the two sets 

 of basidia are so arranged in relation to one another and to the 

 paraphyses that they form a beautiful mosaic-work. If one con- 

 siders the area shown in Fig. 60 at C, it is clear that it would be diffi- 

 cult to crowd in more than one or two additional basidia, provided 

 that the new spores were to be at the same level as the others and 

 were to keep a safe distance from neighbouring spores. Yet, owing 

 to the dimorphism of the basidia, all the spores shown at D were 

 actually crowded with perfect safety into this very area, as shown 

 at B. These considerations, based on accurate camera-lucida 

 drawings, seem to show in the most conclusive manner that the 

 dimorphism of the basidia is correlated with fruit-body economy. 

 Dimorphism has this advantage over monomorphism : it permits 

 the number of spores which can be developed in safety {i.e. without 

 danger of jostling) at one and the same time on any given area to 

 be greatly increased, nay, practically doubled. In a Coprinus, the 

 importance of crowding into any small area of the hymenium the 

 maximum number of ripe spores at one and the same time is easily 

 perceived when one recollects : firstly, that the zone of spore- 

 discharge passes from below upwards on each gill once only, so that 

 it traverses a band of the hymenium, say 0-1 mm. wide, in a very 

 few minutes, and, secondly, that autodigestion quickly destroys 

 those parts of the gills which have shed their spores. With the 

 imposition of this time-limit, it is impossible in a Coprinus to increase 

 the number of spores produced on any small area of the hymenium 

 by developing a long series of strictly successive generations of basidia, 

 as is done, for instance, in Panaeolus campanulatus. The only 

 suitable method for bringing about such an increase seems to be that 

 actually employed, namely, differential protuberancy of the basidia, 

 which in Coprinus comatus is expressed as dimorphism, combined 

 with lateral crowding. 



When writing the account of Coprinus comatus given in the first 

 volume of these Researches, I was puzzled to explain the striking 

 protuberancy of the basidia which I had observed ; but I had not 



