COPRINUS MICACEUS 347 



but, as the pileus enlarges and opens out, they grow in size, thus 

 enabling the hymenium to increase in surface area and so keep pace 

 with the growth of the subhymenium and trama. 



Another piece of the hymenium which happened to include a 

 cystidium is shown in Fig. 155 at C. The cystidium has a diameter 

 which is enormous relatively to the diameters of the basidia, and it 

 is surrounded by paraphyses. For every cystidium there are thou- 

 sands of basidia and paraphyses, so that, in comparison, cystidia 

 are rare elements in the hymenium. 



In Fig. 155 at A is shown a piece of the hymenium complete 

 with basidia, paraphyses, and spores. The spores were drawn with 

 the camera lucida from living material, so that their positions are 

 true to nature. The basidia and paraphyses were added semi- 

 diagrammatically. Optical difficulties prevent one from making a 

 camera-lucida drawing of any one hymenial area that is complete 

 in all its details. The spores must be surrounded by air when they 

 are drawn, as the addition of water to the hymenium usually results 

 in many of them being dislodged from their sterigmata ; but, in air, 

 it is difficult to see the outlines of the paraphyses on account of the 

 presence of the spores above them. Since water removes most of 

 the ripe or almost ripe spores from their sterigmata, when one 

 desires to make drawings of the basidia and paraphyses it is advisable 

 to mount the gill in water. Other investigators do not seem to 

 have attempted to draw complete and satisfactory surface views 

 of the hymenium of Coprini ; but, as we have seen, the difficulties 

 in the way of accomplishing this are not insuperable. 



Occasionally, trisporous basidia occur among the quadrisporous, 

 just as in the hymenium of Coprinus sterquilinus, C. niveus (Vol. II, 

 Fig. 110 b, p. 320), etc. ; and two are present in the hymenium 

 represented in Fig. 154, one in C and one in D (p. 345). 



The cystidia vary from 100 to 150 y^i in length and from 40 to 

 65 fi in width and, relatively to the basidia and paraphyses, are 

 elements of gigantic size. In shape they are either elongated-oval, 

 or they are cylindrical in the middle and bluntly rounded at each 

 end like straight sausages. They are almost sessile on the sub- 

 hymenial cells from which they arise, and it is only with the greatest 

 difficulty that one can sometimes find a trace of a very minute stalk. 



