X59 



sto-nce 

 invest 



, in Abl 9B cephalonlca . which Maule (loc. cit. p. 18) 

 igated fKorbughlyl, 



Wound wood does not always appear as stratified tissues 

 to be considered as a direct continua.tion of the normal wood. 

 In the oanbial callus of cuttings, which swells out over the 

 place of injury, separate cells often assume the character of 

 parenchjmiatic tracheids as described above. In the production 

 of these v/e may recognize the beginning of the formation of 

 wound-wood. Wot infrequently, tracheid-like cells lie in the 

 callus, united into ball-like groups. In both cases the abnor-< 

 mal tracheal elements remain separated from the normal wood. 

 In the further course of development independent cambial, or 

 meristematic tissues are formed in the periphery of the tracheid 

 groups, through whose capacity for division these groupB may be 

 greatly enlarged. The new ebnorraal cambial tissues can also 

 remain permanently separated from the normal cambial ring. 



In spite of the universal similarity in the structure of 

 wound wood in different plants, differences may also be proved 

 in the individual species. Besides the different quantative 

 proportions between tracheid-llke elements and those resembling 

 medullary rajr parenchjTna, besides the formation of the resin 

 ducts already mentioned, etc^, the irregular, waved course of 

 the fibres of wound wood elements comes under consideration 

 and has been clearly recognized in macroscopic investigation, 

 fl77) As is already known, the structural appearance, conditioned by 

 the irregular course of the fibres, has been termed gnarled 



It is well to observe here^that these abnormal resin 

 containers do not exhibit the structure of normal resin ducts 

 in conifers; "in particular, the epithelial cells lining the 

 ducts are lacking in these . The longitudinal course of the 

 eingle resin containers was always x->arallel to the course of 

 the wood fibre;- besides, this course was often interrupted 

 by a bridge, several cells wide, of parenchymatic elements, 

 so thr.t there was not present an actual resin duct, but a con- 

 tiniious row of resin containers, the length of which exceeded 

 three or four times the wid^h". In addition to this, many 

 circtxmstances point to the fact, "that they do not serve for 

 the continued secretion of resin, but only as store rooms for 

 resin, which was formed in the wound callus, the transference 

 of which to the bark has become^^ impossible on account of the 

 wood mantle lying on this", (Maula, loc. cit. p. 18, 19. 

 Compare also the further statements on abnormal formation of 

 resin ducts in the discussion of gall-wood) . Just because the 

 formation of the characteristic epithelium is not present in 

 the abnormal resin containers and because we are concerned in 

 them only with "ordinary" parenchyma cells, which have been 

 filled with resin, every reason is lacking for seeking new 

 kinds of differentiation processes in the occurrence of the 

 abnormal resin ducts, as wijtl be observed in prosoplasmas. 

 The game holds good for the wood parenchyma cells, which de 

 Vries found in the v/ound wood of Oaragana. 



