EXPLANATION OF PLATES 1 -V 



PLATE I 



Fig. 1. — Coprinus comatus. Vertical section through a large fruit-body showing 

 the thin flesh, the vertically-placed gills, darkening from below upwards, and the 

 hollow stipe, m, marginal band covered with cystidia. Natural size. 



Fig. 2. — PsaUiota campestris. Section through a rijje fruit-body at maturity to 

 be contrasted with that of Coprinus comatuH in Fig. 1. Its flesh is thick, and the 

 gills are nearly horizontally outstretched. Specimen obtained from a field. 

 Natural size. 



Fjg. 3. — Section through the hymenium of Pohjporus squamosus, constructed 

 from sketches made with a camera lucida. «, a basidium with unripe spores ; h, 

 a basidium with ripe spores ; c, a basidium with two of its spores already dis- 

 charged ; d, a basidium which has discharged all four spores. Paraphyses separate 

 the basidia. Magnification, 625. 



Fig. 4. — PsaUiota canipestris. Vertical and transverse section through three 

 gills. The hymenial surfaces are almost vertical. The arrows indicate the spora- 

 J)olas or paths described by spores after violent discharge from the sterigmata. 

 Each spore is shot outwards horizontally to a distance of 0*l-0'2 mm., and after 

 making a sharp turn falls vertically downwards in the space between the gills. 

 Magnification, 25. 



Fig. 5. — Coprinus comatus. Transverse section through some of the gills 

 whilst the spores are ripening, s, s, spaces between the gills lined by the 

 hymenium ; e, inner swollen edges of gills covered with cystidia ; /, pileus flesh. 

 Magnification, 8. 



PLATE II 



Figs, all of Coprinus comatus. 



Fig. 6. — Vertical section through a young fruit-body shortly after it had 

 appeared above the ground, s, level of soil. Natural size. 



Fig. 7. — Vertical section through an older fruit-body shortly before the gills 

 separate from the stipe, .s, level of soil. Natural size. 



Fig. 8. — Vertical section through a fruit-body after autodigestion has begun. 

 The gills are becoming liquefied from below upwards. The dotted lines show the 

 shape and position of the gills at the moment autodigestion began. -s lower 

 edge of gill where spore-discharge and subsequently autodigestion first become 

 active ; a, oblique edge of gill where spore-discharge and autodigestion are taking 

 place ; m, marginal band on gill edge covered with cystidia. Natural size. 



Fig. 9. — Vertical section through a fruit-body which has become helmet- 

 shaped. By autodigestion the gills have now become reduced to about one-third 

 their original length. «, edge of gill where spore-liberation and autodigestion 



270 



