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RESEARCHES ON FUNGI 

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FIG. 146. Psalliota campestris (cultivated form). Semi-diagrammatic surface view of the living hymenium of a 

 Mushroom, about 24 hours after the beginning of the spore-discharge period. The [length of each side of the 

 square is 0-1 mm., so that the area of the square is equal to 0-01 of a square mm. All the elements belong to 

 one or other of the following five groups : past-generation basidia, a a : present-generation basidia, b b ; coming- 



generation basidia, c c ; future-generation basidia, d d ; permanently sterile paraphyses, 



A wave of de- 



velopment is proceeding from the light area on the left to the dark area on the right in the directions shown by 

 the arrows. The series 1 to 7 are basidia in successively younger stages of development. No. 1, basidia with 

 spores which are full-sized but young (only about 1 hour old) and unpigmented ; no. 2, basidium with spores 

 not yet of full size (about 30 minutes old) ; no. 3, basidium with spores only one-third of their eventual 

 diameter (about 10 minutes old) ; no. 4, basidium with spores which have just begun their existence (about 

 5 minutes old) ; no. 5, basidia with sterigmata fully developed but no spores ; no. 6, basidium with sterigmata 

 just beginning to develop ; no. 7, basidium as yet without even a trace of sterigmata. Nos. 1 to 4 belong to 

 the present-generation basidia of the light area, while nos. 5 to 7 belong to the coming-generation basidia of the 

 dark area. Spore-discharge is taking place at the left-hand side of the dark area. The basidia * s have just 

 discharged their spores and are collapsing ; their sterigmata are sinking into a concavity which is forming at 

 the- end of each basidium-body. The basidium w is just discharging the second of its two spores and, as a pre- 

 liminary thereto, a drop of water has been excreted within the last 10 seconds at the spore-hilum. Most of the 

 basidia of the present generation are bisporous, b b ; but, here and there, certain basidia are monosporous, 

 m m, and have larger spores. A past-generation basidium, if it has two sterigmatic stumps, has been 

 derived from a bisporous basidium ; but, if it has only one such stump, as shown at cm, it has been derived from 

 a monosporous basidium. An undischarged or waste spore lying on its side and adherent to the surface of 

 the hymenium is shown at u. (The present-generation baridia are identical with those shown in the right 

 two-thirds of Fig. 142.) Magnification, 1,060. 



