(110) 



103 



towards the inside and displaces its neigh- 

 boys. The wart can then be termed "half- 

 composite". Finally, however, it may happen- 

 and this is found to take place in all pe- 

 duncles,- that a one or more layered, cup- 

 like covering groves about the nutritive cell» 

 as in the case of Synchytrium Mercuriales. _ 

 It is there designated as a composite wart.-'- 

 In Ludi^'s contributions are found also refer- 

 ences to those of earlier authors upon this 

 qquestion. 



The fact that after infection v/ith Synohtria and dur- 

 ing the abnormal growth of the "nutritive cells", appreci- 

 able amounts of nutritive stuffs may indeed be brought to 

 them, as stated above under gall hypertrophies in general, 

 is proved first and foremost by the growth and increase of 

 the parasite, lo other means of nutrition are at its dis- 

 posal than these contained in its nutritive cells In vig- 

 orous consumption, however, there does not occur any strik- 

 ing accumulation of proteins, which is characteristic of 

 many other hypertrophies. The formation of red coloring 

 matter has "been observed repeatedly in infected cells, 



ERIHEUM- STRUCTURES 



As the second group of the gall-hypertrophies "of the 

 epidermis, there follov/s that of Brineum>-structures , v/hich 

 surpass in diversity of form all other hypertrophies known 

 in the plant kingdom. 



In the accepted text books of plant pathology all 

 those mite-galls are summarized as felt-galls or Erineum- 

 structures, v/hich appear to the naked eye as "felt-like 

 coatings" of the infected plant organ. This limitation may 

 suffice for the needs of the practical v/orker, but for our 

 purpose a sharper formulation might be advisable. In cross- 

 secjions of the diseased leaf, etc. it is shovm, that the 

 felt-like covering has been produced only by the outgrowth 

 (hypertrophy) of epidermal cells (compare fig. 38) , or that 

 besides the hairs ^ multicellular cones and ridges have been 

 produced by the excrescence of the fundamental tissue. Felt- 

 galls of the second kind will be mentioned in the chapter 

 on hyperplasia. In the present chapter, we are concerned 

 only with the first named case. As Erineum-structures we 

 vail consider in the following only those variations from 

 the normal v/hich are caused by mites, and which like many 

 Synchytrium galls, are characterized by hair-like hyper- 

 trophy of the epidermal cells. 2 The knov/ledge of the Erinea 



1. Ludi, loc, cit, p. 8. 



2. I consider it expedient to retain the old designation 

 "Erineum" , in spite of the change in meaning of the word 

 since Persoon. (see belov/) . On the other hand, it appears 

 to me inexpedient, at the least very unnecyBssary, to pro- 

 vide the newly found Erineum structureis (from the standpoint) 

 of the binominal method of nomenclature) with a particular 

 "species" naipe. 



