406 MB. E. DABWLtf ON THE 



The Theory of the Growth of Cuttings ; illustrated by Observa- 

 tions art the Bramble, Bubus fruticosus. By Fbancjs 

 Dabwin, F.L.S. 



[Read December 16, 1880.] 



Theory of the Growth of Cuttings. 



When a cutting (for instance, a piece taken from the branch of 

 a "Willow) is placed in damp air, it produces roots at the lower 

 end, while the buds at the upper end grow out into branches. 

 The question as to what are the causes which determine the roots 

 and branches to grow at these places has lately attracted a good 

 deal of attention among physiologists. The works which are of 

 especial importance on the subject are Yochting's ' Organbildung 

 im Pflanzenreich ' * and Sachs's paper " Stoff und Form der Pflan- 

 zenorgane"t. Sachs's essay is in some measure a critique on 

 Vochting's work, and the latter author has replied in a paper in 

 the ' Botanische Zeitung ' (1880, p. 593). 



Vochting divides cuttings into two chief classes. First, 

 there may be cuttings which consist of a simple piece of stem or 

 branch, without buds (which may be either absent or destroyed), 

 and without those beginnings or rudiments of roots which are 

 called in German " Anlagen." When such a cutting develops 

 buds, they must of course be adventitious ones ; therefore both 

 the branches and the roots produced by the cutting must be new 

 growths, formed after the cutting has been separated from the 

 mother plant. In these cuttings the roots tend to be developed 

 at the basal % end (in ordinary cases that which was the lower 

 end when the twig was attached to the plant), while the branches 

 grow at the opposite or apical end. And these growths take 

 place, in large measure, independently of the external forces, light 

 and gravitation. Thus (to confine the discussion to the effects 

 of gravitation) the growth is of approximately the same character 

 whether the cutting is placed with its basal end upwards or down- 

 wards. When a branch is divided into a number of cuttings, 

 each of which produces roots at its basal and branches at its apical 



* Bonn, 1878. 



t Arbeiten des bot. Inst, in Wiirzburg, 1880, p. 452. 



% "Basal" means tbe end of a stem or branch which is nearest the root of 

 the parent plant. " Apical " means the opposite end. 



