PSALLIOTA CAMPESTRIS 447 



past-generations basidia or paraphyses. No present-generation 

 basidium happened to be included in the area. 



Camera-lucida Studies of a Completely Exhausted Hymenium. 

 The studies of the hymenium represented in Fig. 152 were made 

 upon a completely exhausted mushroom which had discharged 

 spores for six days and six nights. The sections were cut with 

 a hand-razor a few hours after the last spores had been shed. In 

 many of the cross-sections, one of which is represented at A, only 

 the paraphyses could be made out, and the basidia, all of which 

 belonged to past generations, were only represented by their 

 gelatinised remains. In Fig. 152, A, the hymenium Ti is composed 

 of paraphyses which still have clear outlines. All these cells were 

 devoid of protoplasm and in this respect resembled the cells of 

 the subhymenium s and trama t. The paraphyses, p, evidently 

 correspond to the elements nos. 18, 19, 20, 21, and 22 in Fig. 148 

 (p. 438) and to nos. 13, 14, 15, 16, and 17 in Fig. 149 (p. 440). They 

 were smaller when the hymenium began to discharge spores and 

 have become somewhat swollen during the gradual exhaustion 

 of the hymenium. The paraphyses, g g, appear to have arisen as 

 outgrowths from the uppermost subhymenial cells, i.e. from cells 

 like nos. I, II, III, IV, and V in Fig. 149 (p. 440) and like the ceUs 

 upon which the paraphyses nos. 18, 19, 20, and 21 are situated in 

 Fig. 148 (p. 438). The past-generations basidia have disappeared 

 except for their gelatinised remains, which are indicated at r r. 

 There are a number of waste spores, w, lying on, and adherent 

 to, the hymenium. 



In the drawing B of Fig. 152 is represented a piece of a section 

 of the totally exhausted hymenium in which, in addition to the 

 paraphyses p, two past-generations basidia can still be recognised 

 at b. Their bodies were very faintly outlined and are so short 

 that there can be little doubt that their sterigmata were among 

 the last to produce spores. The subhymenium is shown at s, and 

 a waste spore at w. 



The surface view of the exhausted hymenium shown at C 

 corresponds to the section at A. The only elements we can clearly 

 distinguish in it are the paraphyses p. The gelatinous remains 

 of the basidia fill the spaces between the paraphyses and are 



