PART FIRST. 



CHAPTER I. 



THE PARASITIC FUNGI. 



The true Fungi, together with the Myxomycetes or Slime-fungi, 

 and the Schizomycetes or Bacteria, constitute a group of the 

 Cryptogams characterized by lack of chlorophyll. In consequence, 

 the members of the group are unable to utilize light as a source 

 of energy, and must obtain their food as organized material, 

 complex in comparison with the simple substances required by 

 green plants. These fungi, in short, are, in common with animals, 

 ultimately dependent for the greater portion of their support 

 on living or dead chlorophyllous plants. According as they 

 obtain nutriment from dead organic remains or from living 

 plants or animals, we distinguish them as Saprophjrtes and 

 Parasites respectively. The same mode of nutrition is found 

 in the case of most non-chlorophyllous Phanerogams, and also 

 in a few chlorophyllous plants, both Cryptogams and Phanero- 

 gams. 



When parasitic Fungi, Bacteria, and other lower organisms 

 attack higher plants, they, as a rule, endeavour to penetrate the 

 living organs of their host. It is only when this penetration 

 has taken place to some extent, and the parasite has thereby 

 come into more or less close contact with the tissues of its host, 

 that conditions suitable to a parasitic mode of nutrition are 

 established. 



To deal with the lower forms of vegetable parasites, with their 

 relations to their respective hosts, and with the structural altera- 

 tions which they bring into existence in the latter, is our object 

 in the present book. 



A 



