COPRINUS STERQUILINUS 



205 



their sides is undergoing important developmental changes. If 

 examined in face view at the time indicated, the hymenium has the 

 appearance shown in Fig. 87 at A. At this stage of development 

 the paraphyses are still very small and rudimentary, but the basidia 

 are well advanced. The bodies of the basidia have already attained 

 their full growth both in width and length, but as yet they bear 

 no spores and have not 

 even begun to develop 

 their sterigmata. Care- 

 ful focussing up and 

 down reveals the fact 

 that the basidia can be 

 divided into their two 

 classes, long and short, 

 so that it is evident that 

 the pattern of the hy- 

 menial mosaic-work has 

 been already established. 

 The bodies of the basidia 

 develop to their maxi- 

 mum thickness, and 

 therefore attain their 

 maximum lateral exten- 

 sion, much sooner than 

 do the paraphyses. This 

 fact is brought out in a 

 striking manner by comparing the area of the hymenium which 

 has just been described (Fig. 87, A) with an area of equal size 

 obtained from the same fruit-body 36 hours later (Fig. 87, B). 

 Such a comparison shows that, whereas the diameters of the 

 basidia have remained unaltered, the areas of the outer surface 

 of the paraphyses have been increased to some three or four times 

 what they were originally. In the drawings of Fig. 87, for the sake 

 of distinction, the long basidia have been represented in uniform 

 black and the short basidia have been shaded ; but there are no 

 real colour-differences between the long and the short basidia when 

 seen with the microscope. 



Fig. 87. — Coprinus sterquilinus. Development of 

 paraphyses. A, plan of surface view of very- 

 young hymenium before the formation of 

 spores. The basidia liave attained their maxi- 

 mum diameter but tlie paraphyses are still 

 rudimentary ; a, a long basidium ; b, a short 

 basidium ; c, paraphyses. B, plan of fully 

 extended hymenium after the spores have been 

 developed ; a, a long basidium ; b, a short 

 basidium ; c, paraphyses. The paraphyses 

 have become greatly swollen, so that there 

 are now only 16 basidia in the area instead of 

 the 27 shown in A. Magnification, 287. 



