428 
Buller. — The Reactions of the Fruit- Bo dies of 
Some of the rotten blocks were placed in a damp-chamber in complete 
darkness. Under these conditions numerous papillae were formed which 
developed into protuberances (Figs. 12 and 13). Light is therefore not 
neccessary for their formation. The direction in which the papillae grow 
in reference to the substratum was carefully noted. It was found that, 
whereas the majority grow out more or less perpendicularly to the wood 
surface (Fig. 13), others grow at angles of 45 0 and a few quite parallel to it 
(Fig. 12). It seems that the direction of growth of the protuberances is not 
determined directly by the substratum, or, in other words, that no somato- 
tropic stimulus is given by the wood. On the other hand, the direction of 
growth appears to depend on the position of origin of the papillae on the 
mycelial layer covering the wood. If a papilla arises towards the centre 
of a mycelial layer which covers a flat wood surface uniformly, it grows 
out perpendicularly to the mycelial covering and incidentally perpendicularly 
to the surface of the wood (see the diagram, Fig. 21). If, however, as I 
frequently observed, the mycelial layer arising on a flat wood surface has 
rounded edges and papillae arise on such edges, then the conical protuberances 
(Fig. 21 ,0 and# 1 ) grow perpendicularly to the mycelial layer and consequently 
obliquely to the wood surface (Figs. 12 and 19). Hence the conclusion 
seems to be justified that the wood exercises no somatotropic stimulus. 
The protuberances develop in the dark into cylindrical rods, which are 
pointed at the free ends (Figs. 12, 13, and 17). The rods are quite white. 
Their growth is terminal. They show absolutely no reaction to the stimulus 
of gravity. In this respect they resemble the hypocotyl of the Mistletoe 
( Viscum), which maintains any direction of growth which it may originally 
have assumed 1 . They neither curve upwards nor downwards, nor, when 
growing at an angle of 45 0 to the vertical (Fig. 12), do they show any 
tendency to take up a diageotropic position. They simply grow in fairly 
straight lines and are, therefore, rectipetal. 
The fruit-bodies, which develop in the dark, never show the slightest 
trace of a pileus, and are, therefore, entirely monstrous and abortive 
(Figs. 12, 13, 17, 19, and 20). They present a very curious appearance, 
and look more like Clavarias than anything else. Cooke 2 has figured in 
his Illustrations of the British Fungi some similar monstrosities obtained 
from a brewery cellar. 
Growth of the unpileated rods continues in the dark for an astonishingly 
long time as compared with normal fruit-bodies growing in light. A number 
of rods were still growing at the end of two months, and some after three 
months, whereas under good light conditions normal fruit-bodies were 
found to come to maturity in less than three weeks. In the course of time 
the monstrosities become very much elongated. One of the most vigorous 
1 Duhamel. Quoted from Vine’s Lectures on the Physiology of Plants, p. 458. 
a Illustrations of British Fungi, PI. 1141. 
