LEPIOTA CEPAESTIPES 



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Fig. 6, B. Although the gills are very lightly built and very 



thin, they are fairly rigid. The rigidity, in part at least, must 



be due to the play of the opposing strains and stresses which 



have been discussed. In this respect we have an analogy with 



the rigidity which is found in young green shoots of Flowering 



Plants. 



The subhymenium is composed of relatively small cells of various 



shapes. To the 



innermost ones are 



attached the large 



tramal cells, and 



from the outer ones 



spring the elements 



which make up the 



hymenium. 



The Hymenium. 



— The hymenium on 

 the sides of the gills 

 is composed of two 

 perfectly definite 

 and easily distin- 

 guishable kinds of 

 cells — the basidia 

 and the paraphyses. 

 Cystidia are absent 

 from the gill-sides 

 but form a fringe along the free gill-margins. To these fringing 

 cystidia we shall return later on. 



The general surface of the hymenium, after the spores have all 

 been shed, presents the appearance shown in Fig. 7 at B. It is 

 evident that the groundwork of the hymenium is made up of the 

 paraphyses. These form a firm pavement in which, at fairly 

 regular intervals, are set the projecting basidia. As if to strengthen 

 the hymenium, adjacent paraphyses are welded together, and they 

 therefore all form part of a continuous membrane. Each basidium 

 is surrounded and isolated by four or five paraphyses, so that no 

 two basidia ever come in contact with each other. Small areas 



Oi^ 



Fig. 6. — Lepiota cepaestipes. Thin sections taken 

 transversely through an unexpanded pileus, lying 

 in water. Effects of tensions in the gills. A, 

 pileus-flesh with three gills attached. The two 

 sides of each gill below have curled in opposite 

 directions. B, two gills showing the same curling 

 as in A ; where the gills are connected, a loop has 

 been formed which tends to push the gills apart. 

 C, fragment of a gill in which the curling of the 

 sides is seen at both ends. D, strips of hymenium, 

 together with the subhj-menium, which have curled 

 up, the lower one into a spiral. Magnification, 15. 



