152 



Origin of Parasitism in Fungi. 



[JUNE, 



shipment, one showing the f.o.b. (free on board) price at port of 

 shipment, and another the c.i.f. (cost, insurance and freight), 

 or otherwise duty will be charged on the latter price instead of 

 on the former. This applies to all produce, and to other ports 

 as well as Durban. 



Mr. George Massee, a Principal Assistant in the Herbarium 

 of the Royal Botanic Gardens, Kew, has contributed to the 



research also throws much light on the factors that determine the 

 immunity of certain species of plants and even individuals to the 

 attack of specific fungi. It is well known that certain parasitic 

 fungi have the power of attacking with ease definite crops, 

 whereas they have no power to enter the tissues of other crops, 

 even though they be closely related. It has also been found that 

 even varieties of some particular species of plant may be resistant 

 to the inroads of a parasite, while other varieties may at once 

 succumb. For example, some wheats are much more resistant 

 to'rust than others, while during the past few years varieties of 

 turnip have been raised which have special power of resistance 

 to the attack of the parasite that causes " finger and toe." 

 This immunity or comparative immunity has attracted the 

 attention of many scientific workers, and now Mr. Massee claims 

 to have discovered its cause. Formerly it was held that an 

 individual plant was liable to invasion by a fungus, or not, 

 according to the condition of the atmosphere at any particular 

 time, or owing to the special development of the cuticle covering 

 the leaves or stem. Should the latter be specially strong, then 

 it was believed that the fungus might find it impossible to enter ; 

 on the other hand, if the cuticle was specially thin, the fungus 

 would have little difficulty in effecting an entrance. Mr. 

 Massee's researches, however, go to show that small differences 

 in character of the sap of the plant are probably the main 

 determining causes as to whether the fungus shall be able to 



Origin of 

 Parasitism in 

 Fungi. 



Philosophical Transactions of the Royal 

 Society of London an interesting account 

 of investigations that he has carried out on 

 the origin of parasitism in fungi. The 



