847 



rooted cabbages on Alliaria and this on the green cabbage. He found mor- 

 phological and anatomical differences in the plants produced from the seed 

 of the grafted specimens. Under this head belong also potato grafting 

 experiments and the grafting of Solanum Lycopersicum on potatoes. In 

 regard to the grafting of various Solanaceae on each other there exist very 

 many experiments which we have described more fully in the second edition 

 of this manual (cf., p. 692 ff). The most thorough experiments, continued 

 up to the present time, are those by Lindemuth, whose investigations have 

 been considered under the section on Albinism (cf., p. 677 ff). Molisch^ 

 has repeated earlier experiments and, agreeing with Strasburger and 

 Vochting, has arrived at the conclusion that the production of graft hybrids 

 may well be explained theoretically but has not actually been satisfactorily 

 proven since, as he says, he and the others had found that scion and stock 

 always retain their morphological character. 



We are not able to share this point of view since Lindemuth's- latest 

 experiments, as well as those of E. Baur, sufficiently demonstrate the influ- 

 ence of the scion on the stock. Nevertheless, bud variations in many cases 

 are also found which have nothing to do with the material influence of the 

 scion on the stock but are probably traceable to wound stimulus. Arrest- 

 ment phenomena of very dift"erent kinds, as, for example, increased pressure 

 in the bud, can initiate a different development of the young axis. 



The influence of the stock on the scion is a well known fact in horticul- 

 ture. We will recall only the different effect of the stock on one and the 

 same apple variety. Grafted on Doucin, a stronger wood growth and a 

 later fertility was produced, on Paradise stock a lesser wood growth and an 

 earlier setting of fruit. No general rule may be laid down. The result 

 depends not only on the plant variety but also on the accessory conditions 

 (age, habitat, form of nutrition, etc.). 



The Natural Processes of Coalescence. 



Very frequently we find in hedges the union of two branches, which 

 oftentimes have grown toward each other from opposite directions*. The 

 same phenomenon may be observed in roots in dense tracts of trees. 



The root fusions can take place in a young stage of the organ at a time 

 when the epidermis is still capable of division. According to Franke^ this 

 process appears in the ivy {Hedera Helix) and the wax flower {Hoy a car- 

 nosa), in both of which plants the epidermal cells of two adjacent roots 

 grow toward each other like papillae and unite. These cells then divide and 

 thereby produce a few layers of connecting tissue. This, however, does not 

 have the firmness of the connecting tissue produced from the cambial zone 



1 Molisch, H., tJber Pfropfung-en. Lotos 1896; cit. Bot. Jahresber. 1S97, I, p. 155, 



2 Lindemuth, H., Kitaibelia vitifolia Willd. mit g-oldg-elb marmorierten Blattern! 

 Gartenflora 1889, p. 431. tJber Veredlung-sversuche mit Malvaceen. Ibid. 1901, No. 1. 



3 Franke, Beitrage z. Kenntnis der Wurzelverwachsung-en. Beitrage z. Biologie 

 der Pflanzen von F. Cohn, VoL III, Part 3; cit. Bot. Centralbl 1SS2. Vol X No 11 

 p. 401. ' ■ ' 



