214 



fnd^?hr«,Sl '^^'^''''l ''^*^'' content of the mechanical tissues 

 ?herebt b?inX^n5^,^^°'''''^ t'^ ^^^Oually strong contraction; 

 xnereoy bringing about a rupturing of the ealltlspuft Thft 

 undeterminable ?I)iptera?) gall o An Anherl?Iee^ is ?ery 

 (fi^ ??!? ?S?f r^''*'^\ Across.section through the |a?l shows 

 lP/19) nftifo ;>i?J ^® Tneohanical mantel consists of two isolated 

 (249) parts A flat cover-like plate of tissue lies above the lar- 

 val chamber the edges of which extend over and around the 

 Ji'^*^y°^>^v^^. Jowl-like sclereid mantel lying beneath the cav- 

 il?* J?™^'^ ^^^ *^''o are ^ fe^- layers of delicate tissue, mien 

 jne gall dries this tissue degenerates and the cover falls off 

 ivo y*' F^if' *^^! opening the interior of the gall. The me- 

 chanicr.l tissue of the gall illustrated in figure 90 mav indeed 

 function very similarly, but my dried material did not permit 

 ox any op^clusion concerning this. Our mtive flora furnishes 

 lurther examples. At the base of the gall of Hormomy i a fagi 

 (compare fig. 86) a delicately walled zone of separation is re- 

 tained - so that at the time of ripening, the helmet-like 

 part Of the gall lying above this zone is loosened. In the 

 linden gall of Ceeidomyla tlllacea the sclerosized inner part 

 Of the gall, which contains the larval cavity, is squeezed out 

 of the contracting peripheral tissue and the inner gall falls 

 to the ground. Later, as described by Kerner , the gall animal 



fnaws a regular groove in the gall kernel and then pushes off 

 he upper part, like a cover. Figure 112 illustrates this pro* 

 Oess. mirther examples are described in Kerner^ s "Pflanzenleben",. 



Nutritive Tissues 



Those g&ll tissues which are devoured by their inhabitants, 

 or the contents of v;hich at least are of benefit to them, may be 

 termed nutritive tissues. The form of the single cells and the 

 character of their avails are of less interest to us hhre than 

 is their di stribution inside the gall body and the quality of 

 their confenTs I 



The significance of the nutritive tissue in the histology 

 of the gall formation and for the existence and development of 

 the gall anirKils even exceeds that of the protective tissues. 

 Ho gall is without mitritive tissues and these not infrequently 

 represent the chief mass of the gall body. In the discussion 

 of gall hypertrophies and kataplasmas, v/e have already become 

 acquainted with galls in which all the pathological cell pro- 

 ducts, ivithout an exception, bear the character of nutritive 

 ^850) cells. It is usually a qtiestion of the deposition of proteins, 

 of oil and of starch,- as stated above in the disctission of 

 Erineura hairs. The fact is here of interest, that, in proso- 

 plasraas, the "divisdon of ;iabor" among gall tissues produces 

 definite zones, the cells of which "serve" exclusively for the 

 storage of carbo-hydrates or of food stuffs containing nitrogen. 

 Especially in the highly organized cynipides and diptera galls, 

 the layers of the nutritive tissue are extraordinarily sharply 

 set off from the neighboring, mostly sclerosized zones. Lacaze- 

 Duthiers, in his gall anatomy, differentiated an especial 

 "couche alimentaire" (see above). 



According to Professor Kadlkofer's kind determination. 

 For the shipment of material, I wish to thank Mr. Zenker in 

 Bipindi, 



2 ' 



Pflanzenleben, 189B, Bd. II, p. 484. 



