370 



RESEARCHES ON FUNGI 



for the construction of the stipe and pileus are conducted upwards 

 from a hard mass of manure through the base of the pseudorhiza. 

 In support of this view may be cited the analogous case of Collybia 

 radicata in which the whole fruit-body is produced at the expense of 

 a mycelium vegetating in a tree-root buried several inches beneath 

 the soil (Fig. 175, A and B, p. 350). 



In passing upwards through the substratum, the pseudorhiza 

 is doubtless directed, like the stipe, by the stimulus of gravity. 

 Harder and softer parts of the substratum must be traversed. The 

 softer parts are directly penetrated, but the harder ones, such as 

 dense masses of straw, can only be avoided by oblique or lateral 

 growth. Sooner or later, often by a very tortuous course of from 

 three to six inches, the surface of the manure is reached. The 

 twisted pseudorhizae shown in Figs. 181 (p. 361) and 186 tell a 

 tale of obstacles which have been encountered during upward 

 growth and have been grown around. In general, the length of a 

 pseudorhiza varies with the depth in the manure at which the 

 primordium of the fruit-body has originated. 



The older and thinner parts of a pseudorhiza are quite solid, 

 but the younger swollen parts, beneath the base of the stipe-shaft, 

 although often sohd (Fig. 185, D and E, p. 367), are sometimes 

 hollow in the centre (Fig. 185, C). The hollow space, when present, 

 is continuous with- that of the stipe. 



A pseudorhiza, before the pileus has shed its spores, is usually 

 unbranched. Occasionally, how^ever, I have observed indications 

 of the putting out of a branch laterally (Fig. 187, E), but this is 

 very rare. Also, before a fruit-body at the end of a pseudorhiza 

 has shed all its spores, primordia — but primordia only — of a number 

 of new fruit-bodies may be developed on the surface of the 

 pseudorhiza (Fig. 187, B). Nevertheless, I have never seen any- 

 thing corresponding to the illustration published by Weir ^ in which 

 he shows one chief fruit-body as yet unexpanded and four long 

 branches coming from the pseudorhiza and all bearing secondary 

 fruit-bodies of considerable size. However, branching not in- 

 frequently takes place from an old stout pseudorhiza when the 

 fruit-body at its end has shed its spores and withered to the base 



1 J. R. Weir, he. cit., Fig. 21, p. 317. 



