1 8 RESEARCHES ON FUNGI 



cystidia (metuloids), which are very numerous, prominent, and 

 encrusted with calcium oxalate, could not possibly act as spacing 

 agents ; for here the hyrnenium is smooth. Possibly, in this genus, 

 they serve to protect the fruit-bodies from slugs or other harmful 

 animal parasites. The same interpretation might apply to the 

 rigid coloured setse of Hymenochtete, but does not seem suitable 

 for those of some species of the woody genus Fomes, e.g. F. nigricaws 

 and F. salicinvis. 



De Bary's J investigation led him to the conclusion that in 

 Lactarius deliciosus the cystidia arise from ordinary hyphse of 

 the trama, but according to Massee 2 the cystidia of Russula and 

 Lactarius are direct terminations of the laticiferous system. Massee's 

 view is supported by the work of Biffen, 3 who found that in 

 Collybia velutipes the cystidia form the hymenial endings of the 

 conducting hyphse. In these cases, doubtless, the cell contents 

 are of importance, although exactly in what way still remains to 

 be explained. In Russula, at least, they do not seem to render 

 the gills unpalatable to slugs, since these animals are particularly 

 fond of the members of this genus, and often devastate the fruit- 

 bodies in a wood to such an extent that scarcely a single specimen 

 is left undamaged. 



Earlier writers, Corda and others, stated that the cystidia of 

 the fleshy fungi discharge their contents through their apices in 

 the form of drops, but de Bary 4 and Brefeld could never satisfy 

 themselves that this is done spontaneously. However, Massee and 

 Worthington Smith have both upheld the older view. According 

 to Massee, 5 cystidia, when mature, contain glycogen which is emitted 

 through the nipple-like openings at their apices, and poured over the 

 surrounding hymenium, where it serves as food for the developing 

 spores. Smith 6 has figured the cystidia of Co^irinus atramentarius, 

 Gomphidius viscosus, and Agaricus radicatus as large, flask-like 



1 De Bary, Comparative Morph. and Biol. of Fungi, English translation, 1887, 

 p. 304. 



2 G. Massee, Journ. Roy. Micr. Soc., 1887, p. 205. 



3 R, H. Biffen, Journ. Linn. Soc., vol. 34, 1898, p. 147. 



4 De Bary, loc. cit. 5 G. Massee, loc. cit. 



6 W. Smith, Grevillea, vol. x., 1881, p. 77 ; also Gardeners' Chronicle, Sept. 17, 

 1881, p. 367. 



