446 RESEARCHES ON FUNGI 



especially clear in this section. The subhymenium consists roughly 

 of the following four layers of cells : I and II, III to VII inclusive, 

 VIII to X inclusive, and XI to XIII inclusive. Now it will be 

 noticed that the basidia are attached at very various depths to 

 the cells of the subhymenium. The basidia nos. 5 and 7 are 

 attached to the cells XI and XII, respectively, which belong 

 to the deepest layer of the subhymenium. The basidia nos. 9, 

 6, 8, and 4 arise successively at higher and higher levels, and in 

 consequence their shafts are shorter and shorter. 



If one compares the basidia nos. 1, 2, and 3 in Fig. 151, A, and 

 no. 4 in B, i.e. some of the last basidia to produce spores in an 

 old hymenium, with basidia nos. 1, 2, and 3 in Fig. 149 (p. 440), 

 nos. 1, 2, 3, 4, and 5 in Fig. 150 (p. 443), and nos. 4 and 5 in Fig. 148 

 (p. 438), i.e. with some of the earliest basidia to produce spores 

 in a young hymenium, one can at once perceive that the former 

 set of basidia is much shorter than the latter set. The comparison 

 of hymenial sections from a mushroom at different ages seems to 

 show that, in general, the first basidia to come to maturity, i.e. to 

 produce spores, are the longest, the last basidia to produce spores 

 are the shortest, and that there is a tendency to gradual shortening 

 of the basidia coming to maturity as the hymenium becomes more 

 and more exhausted. 



In Fig. 151, C, is shown a surface view of the hymenium taken 

 from the same material as the sections A and B. The hymenium 

 was submerged in water under a cover-glass. Only such elements 

 are shown as could be clearly distinguished. The past-generations 

 basidia, a, were brownish. Their sterigmatic stumps could not 

 be seen ; possibly they were disappearing or had disappeared. 

 The large element & is a coming-generation basidium, and the 

 elements c are paraphyses. As already explained in an earlier 

 section, in the Mushroom, on account of the small size of the 

 hymenial elements, the optical difficulties are too great to permit 

 of one clearly distinguishing all the elements in a face view of the 

 hymenium. The clear spaces left in the drawing C indicate that 

 the cells in those regions seemed too vague and uncertain in 

 their outlines to be worth sketching. The elements which have 

 actually been drawn, with the exception of b, appear to be either 



