PSALLIOTA CAMPESTRIS 431 



The future-generations basidia (nos. 2, 6, 7, 9, 12, 14, 17, 19, 23, 

 27, 29, 31, 34, 37, 45, 49, 52, 54, 59, and 62) are smaller than those 

 of the coming-generation basidia and never bear sterigmata. They 

 are not yet protuberant ; indeed, it is their free ends, together 

 with those of the past-generation basidia and of many of the para- 

 physes, which make up what I have often referred to as the general 

 level of the hymenium, above which the bodies of the basidia of the 

 present-generation and coming-generation basidia project by about 

 0-005 mm. The basidium-bodies are filled with fine protoplasmic 

 contents. Since the hymenium represented in Fig. 147 is sup- 

 posed to have been discharging spores for only 24 hours and will 

 discharge further spores for some four or five days, the future- 

 generations basidia still outnumber those of the past generations. 



The paraphyses (nos. 1, 4, 10, 15, 20, 22, 25, 26, 33, 35, 39, 40, 

 43, 47, 50, 56, 58, and 63) are permanently sterile : they never 

 produce sterigmata or spores. They are usually attached to the 

 uppermost cells of the subhymenium and are the shortest of 

 the hy menial elements. At the stage of the development of the 

 hymenium shown in Fig. 147 (p. 429), they have not yet grown 

 to their maximum size. As more and more generations of basidia 

 shed their spores and collapse, the paraphyses grow larger and 

 larger in diameter, so that the lateral space which they occupy 

 in the hymenium is progressively increased. Drawings of older 

 swollen paraphyses will be given in a subsequent illustration. The 

 paraphyses in the hymenium represented in Fig. 147 are to a large 

 extent covered laterally by the bodies of the basidia. Owing to 

 their small size in the young hymenium and to the fact that they 

 are largely hidden by the basidia, they are often difficult to make 

 out clearly. At first they contain a large amount of protoplasm 

 in which one can usually detect one or more vacuoles ; but, as 

 they grow older and enlarge, their vacuoles increase in size and their 

 massive protoplasm gradually disappears, so that, finally, in late 

 stages of the development of the hymenium, the lumen of each 

 paraphysis comes to be occupied by one large vacuole. 



Parts of three waves of development are shown in Fig. 147 

 (p. 429) proceeding across the section from right to left. The rear 

 end (about three-ninths) of the earliest wave consists of the series of 



