6 FUNGI. 



as distinct as in tlio flowering plants. In fact, there is still no 

 reason to dissent, except to a very limited extent, from what 

 was written before polymorphism was accredited, that, "with a 

 few exceptions only, it may without doubt be asserted that more 

 certain species do not exist in any part of the organized world 

 than amongst fungi. The same species constantly recur in the 

 same places, and if kinds not hitherto detected present them- 

 selves, they are either such as are well known in other districts, 

 or species which have been overlooked, and which are found on 

 better experience to be widely diffused. There is nothing like 

 chance about their characters or growth." * 



The parasitism of numerous minute species on living and 

 growing plants has its parallel even amongst phanerogams in 

 the mistletoe and broom-rape and similar species. Amongst 

 fungi a large number are thus parasitic, distorting, and in many 

 cases ultimately destroying, their host, burrowing within the 

 tissues, and causing rust and smut in corn and grasses, or even 

 more destructive and injurious in such moulds as those of the 

 potato disease and its allies. A still larger number of fungi 

 are developed from decayed or decaying vegetable matter. 

 These are found in winter on dead leaves, twigs, branches, 

 rotten wood, the remains of herbaceous plants, and soil largely 

 charged with disintegrated vegetables. As soon as a plant 

 begins to decay it becomes the source of a new vegetation, 

 which hastens its destruction, and a new cycle of life com- 

 mences. In these instances, whether parasitic on living plants 

 or developed on dead ones, the source is still vegetable. But 

 this is not always the case, so that it cannot be predicated that 

 fungi are wholly epiphytal. Some species are always found on 

 animal matter, leather, horn, bone, &c., and some affect such 

 unpromising substances as minerals, from which it would be 

 supposed that no nourishment could be obtained, not only hard 

 gravel stones, fragments of rock, but also metals, such as iron 

 and lead, of which more may be said when we come to treat of 

 the habitats of fungi. Although in general terms fungi may 

 be described as " hysterophytal or epiphytal mycetals deriving 



Berkeley's "Outlines of British Fungology," p. 24. 



