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RESEARCHES ON FUNGI 



such a basidium be now looked at in side view in a cross-section of 

 the hymenium, it no longer appears turgid and well-defined, no 

 longer protuberant, but shrunken both in length and breadth, 



a 



B 



y 



FIG. 93. Panaeolus campanulatus. A, the collapse of exhausted basidia, seen 

 in lateral view : a, a basidium with four ripe spores ; 6, a basidium which 

 has shot away two spores and is about to shoot away another spore which 

 has a full-size water-drop excreted at its hilum ; c, a basidium which has just 

 shot away its last spore but still has erect sterigmata ; d, a basidium in the 

 act of collapsing, about 20 minutes after the stage c, the sterigmata are sinking 

 into a concavity forming at the end of the basidium-body ; e, a completely 

 collapsed basidium, the sterigmata in the concavity cannot be seen ; / is e 

 in vertical section, showing the sterigmata in the concavity ; g is / seen from 

 above. B, the tops of certain collapsed basidia which were in a gill mounted 

 in water under a cover-glass. To show how air-bubbles are caught in the 

 concave ends of the basidium-body : a, a basidium without an air-bubble ; 

 b, c, d, e, and/ show bubbles of increasing size. C, the ends of collapsed basidia, 

 as seen in a gill mounted with water below and air above : in b, e, f, g, and i 

 the sterigmata are still distinctly conical, while in a, c, d, h,j, and k the sterigmata 

 are reduced to mere refringent particles. Magnification, 700. 



reduced to about one-third of its original volume, moulded more 

 or less by the pressure of adjacent living basidia and paraphyses, 

 and relatively difficult to observe (Fig. 93, A, e ; also Fig. 96, a, a, 

 p. 287). Its outer end no longer appears convex but flat, owing to 

 the fact that one can only see the rim of the concave depression 

 which has been formed in it. The sterigmata, in such a lateral 

 view of the basidium, cannot be observed at all. This is due to the 



