A Clover Fungus. 



45 



years. The fact, also, that sclerotia are formed upon the 

 roots of the clover plants, and are therefore supplied with 

 moisture and able to germinate and send forth spores in due 

 season, should lead to the ploughing-up of infected clover 

 fields as soon as possible. 



There is a conidial form of the fungus by which infection 

 may be conveyed to clover and other host plants. This is 

 the Botrytis or Polyactis form, which has not been specifically 

 named, but is said by Rehm and other mycologists to exist, 

 and to be a necessary stage in the life history of the fungus. 

 Botrytis cmerea is the conidial form of the allied fungus 

 Sclerotinia Filckeliana^ which causes the " ripe-rot of the 

 grape. In this Botrytis form Scierotinia trifotiorum passes 

 through a stage ot saprophytic existence upon the dead 

 stems and foliage of clover, and other host plants, and on 

 farmyard manure, in order to render it capable of parasitism. 

 Upon this De Bary writes concerning Sderotinia sclerotiorum : 

 — *^Itmay go through the whole course of its development as 

 a saprophyte, and finds opportunity for this in the natural 

 state on dead plants. But it can also attack living and 

 healthy plants and parts of plants as a parasite, and destroy 

 them. But according to our present experience it always 

 requires to go through a previous stage of existence as a 

 saprophyte in order to be capable of parasitism. The allied 

 Sclerotinia ciborioides, which preys on clover plants, behaves 

 in a somewhat similar manner." * Rehm, who is the chief 

 authority on this fungus, speaks of its conidial form, though 

 he does not define it as a Botrytis. 



This clover disease was first seen in Germany, in Hesse, 

 about 1857, and in Denmark in 1870. But the first 

 scientific description of it was given by Kiihn in 1870, in a 

 paper published in the first number of Hedwigia for 1870, 

 page 50, entitled. Prof. Dr. Jul. K'dhn, iiber die Sclerotieji- 

 krankheit des Klees. Then Rehm recorded the results of 

 his careful investigation in 1872 in his work, EntwicJi- 

 elungsgeschichte von Peziza ciborioides, which, is still the standard 

 vvork on this subject, and showed that the disease had done 



*" Op cit., p. 380. 



