PARASITIC FUNGI. 97 



which attack this the most important of all our farm crops 

 or of the best known and most readily available means 

 by which their attacks can be prevented or remedied. It 

 is obvious enough that this department of our series 

 carries with it many considerations of the highest value ; 

 for it is plain enough that we may take the utmost pains 

 to ensure cultivation of our crop, and yet lose it quickly 

 by the ravages of disease, all the more dangerous be- 

 cause so insidious, and the origin and progress of which 

 are so invested with doubt and difficulty. Hence the 

 value to the practical man of that knowledge of these dis- 

 eases which may enable him to prevent their attacking his 

 crop, or of lessening their evils should they unfortunately 

 visit it. Following Professor Henslow's classification of the 

 diseases of wheat, we shall give our notes under the two 

 heads "diseases of vegetable," and second, "diseases of 

 animal or insect origin." 



7. Parasitic Fungi. The diseases which attack the 

 wheat plant, and which come under the first class, owe 

 their origin to the attacks of parasitic fungi. A fungus is 

 a cryptogamous or cellular plant, which grows in contact 

 with organised matter, never drawing its nutriment directly 

 from the soil, water, or atmosphere, like other plants; but 

 living by imbibing from the plant or organised body in 

 which it grows the juices which characterise it. This 

 nourishment is drawn through the medium of the " stalk " 

 or "stem" or "spawn" of the fungus called, in the lan- 

 guage of botany, its " mycelium." The fungus is totally de- 

 void of flowers, but is propagated by what are called 

 "spores," or sometimes "sporules;" these are generally 

 colourless, but if possessed of colour, that is never green. 

 Fungi, as a rule, attain no great size, and are small com- 

 pared with cryptogamous plants, as ferns, to which they are 

 closely allied ; many of them are, however, so wonderfully 

 minute as to require the highest microscopic powers to make 

 their presence manifest ; hence the obscurity under which 

 the subject of the investigation of their habit rests ; and it 

 so happens that it is amongst this class that those fungi 



