PARASITIC FUNGI AND MOULDS. 43 



VI HABITAT OF PARASITIC FUNGI: THEIR DESTRUC- 

 TIVE ACTION. 



The habitat of parasitic fungi is extremely varied. 

 Roumeguere, in his Cryptogamie illustre'e, has devoted 

 more than forty pages of a large quarto, printed in 

 three columns, merely to the enumeration of fungi, 

 classified according to their position in plants, animals, 

 organic or inorganic substances, and the author himself 

 admits that this list is far from complete. 



Parasitic fungi are found on plants belonging to 

 all the families of the vegetable kingdom, and also 

 on other fungi ; on living animals, vertebrate and 

 invertebrate ; on their dead bodies and on excrement ; 

 in stagnant waters and in the sea, on piles and rocks. 

 Others prefer marshes, turf-bogs, heathy ground (which 

 may be marshy or dry), dunes, caves and holes, and 

 even completely covered by the soil, as is the case 

 with truffles. Others, again, grow upon stones, walls, 

 and rocks ; in the open air or in ruins ; or, like Torula 

 conglutinata and Himantia cellaria, in the darkest 

 caves, where they form a species of feltwork, often 

 several centimetres in thickness, of a blackish colour, 

 ragged, and extremely light, which in the course of 

 a few years overspreads the walls of cellars. Other 

 fungi inhabit our houses, attack our food, clothes, 

 utensils of every kind; wall-papers and books, of 

 which the paste offers a nutriment which they can 



