INJURIES INDUCED BY PLANTS 221 



which contain a plentiful supply of proteid substances. Not 

 only water but also large quantities of nutritive substances are 

 apparently conveyed in these vessel-like organs from the nutrient 

 substratum that is to say, the woodwork to the more remote 

 portions of the growing mycelium. Now, as these strands attain 

 to a length of many yards, and by taking advantage of depres- 

 sions in walls mount from the cellar to the ground floor, and 

 from there to the upper stories, it is easily seen that the fungus 

 may occur in parts of a building in which there is absolutely no 

 woodwork, without having 'encountered any nourishment that 

 is to say, wood on its way. Of course those strands do not 

 advance as such. It is the delicate filamentous mycelium which,, 

 supplied with water and nourishment from the strands behind, 

 and taking advantage of every crack and cranny, grows through 

 walls, soil, &c. The chink in a wall which was entered at first 

 by a delicate floccose mycelium later on contains a thick strand, 

 which, however, has gradually developed from the former. 

 Should the mycelium during its progress again gain access to 

 woodwork, it destroys the latter, the delicate filaments entering 

 and abstracting the nourishment, and thus gaining strength for 

 more vigorous development. It is characteristic of M. lacry- 

 mans that it is able to destroy even dry woodwork. This is 

 rendered possible by the strands conducting enough water from 

 other damp parts of the building to soak the dry wood, and 

 thus make it suitable for attack. In muggy rooms, when wood 

 is not available to absorb the water, the fungus parts with it 

 in the form of drops or "tears," which has gained for it the 

 name of the " weeping " house-fungus (lacrymans}. 



If sufficient space be available, and as a rule in the presence 

 of more or less light, though this is not absolutely necessary, the 

 familiar sporophores are formed. Though they vary in form, 

 these are usually of a flat saucer-like shape. The fungus-mass,, 

 which is at first white and loose, assumes a reddish colour in 

 places, and displays vermiform folds, which soon become so 

 covered with rusty spores that the whole surface is coloured 

 deep-brown. The brown spores, which are so small that about 

 sixty-five thousand millions can be contained in a cubic inch of 

 space, display a germ-aperture in the thick wall at one end,, 

 which is closed however by a clear lustrous plug. 



