253 



called forth by injury, v/e find the production chiefly of normal 

 tissue - proliferations of various kinds. In vasoular crjrttogams 

 callus tissues are also rare. Fungi also seem very slothful to 

 reaction. 



Ho instance os knov/n as yet in vrhich cry|)togaras have pro- 

 duced hyperhydric tissues, Tyloses are rare in vasciilrr orjrptogams 



Attention should also be called to the sraall part played 

 by galls on the lover plants. Right here, however, we must re- 

 frain from abstract conclusions as to the cellular capacity for 

 reaction, since :j,ike mcny others, the question bn.s not yet been 

 answered, as to hovr cryptogams react to the poison of gall In- 

 sects v/hich produce prosoplasmas and Inhabit phanerogams if this 

 poison is introduced artificially in the plants. 



If Goebel , in his consideration of the formation of organs 

 in plants, has arrived at the conclusion that lower pj^nts, es- 

 pecially fungi, are more "plastic" for malformations than are 

 higher plants, we can affirm in regsrd to the formation of tissue 

 that higher plants are capable of greater production. Likewise, 

 we find in phanerogams and especially dicotyledons the most ex- 

 tensive formations of tissue as well as the most abundantly and 

 diversely differentiated ones. 



If we compare tissues of different ages with one another, 

 permanent tissues with young tissues, somatic with embryonic, 

 we find that young tissue in many oases exceeds already differ- 

 entiated or completely matured tlissiie in productive ability, but 

 that, on the other hand, in many other cases, the cells of the 

 permanent tissue have also retained their ability to react and 

 can be incited to an extraordinarily lively formation of tissue. 



The fact that the organisms which produce galls seek out 

 young parts of the host plant, in order to incite these to gall 

 formation , has often been treated and was mentioned above (pTH^) 

 "f*Pbciraas, Sachs and others). However, the conditions are not at 

 (S95) all so simple as Sachs*^ assumes;- that gall formations are more 

 abtjuidant and mo re" complicated, the younger the tissue from which 

 tljey are produced. In many cases we findthat, just as richly 

 differentiated abnormal excrescences are produced from tissue 

 already differentiated - and still capable of grow5ih - as from 

 the tissue of the vegetative tip, Appel (loc. cit.) has tried 

 to explain cases of this kind by the statement that in them the 

 producer of the gall is able "to bring tissue already differen- 

 tiated back to its original form, to make embryonic tissue from 

 somatic", so that in the latter instance, embryonic tissue still 

 produces the gall. I have already (lot. cit.) expressed my views 

 against this theorjr and have referred to the fact that the embry- 

 onic tissTie produced from the somatic under the influence of 

 gall-stimulus represents in itself the young gall. V/ith its pro- 

 duction is proved the ability of the differentiated tissue to pro- 

 duce abnormal richly differentiated gall products from itself. 

 In my opinion it would be absolutely unjustlfieble to fering the 

 differentiation of the ggll products into interdependence with 



Organographie, 1898, Bd. 1, p. I'^l* 

 ^ Phyeiol. Notizen, VII fFlera, 1892, Bd, LXXVII, p. 240). 



