PROBLEMS OF PROPAGATION. 



447 



PEOBLEMS OF PEOPAGATION. 



By Peof. I. Bayley Balfour, F.E.S., V.M.H. 



[Read June 4, 1912; Sir Daniel Morris, K.C.M.G., V.M.H., in the Chair.] 



[Being the eighth "Masters Lecture."] 



" Problems of Propagation " is a comprehensive title for my 

 lecture, and I will therefore at the outset relieve expectation by saying 

 that I propose to address you to-day from a definite text. I read in a 

 recently published book this : " It is well known that many plants — 

 Pinus, for example — cannot be propagated from cuttings." 



If that statement be correct the question is raised — Why is it so? 



If the statement be incorrect Vv^e may as fairly ask — Why is it so 

 often made? 



Whether correct or incorrect the statement is one to which a large 

 part of the gardening world will subscribe — and in many cases on the 

 ground of practical experience. 



The importance of the point involved in the statement has been 

 brought home to me recently with some force. 



Last year a large nurseryman with an extensive business in Y/est 

 Scotland, showing me a multitude of young grafted plants of the 

 charmingly graceful Gypsophila paniculata ftore pleno, asked if I could 

 tell him why it was impossible to propagate the plant by cuttings. 

 I had not heard until then of the difficulty — although I have learned 

 since that it is frequently experienced — and could only promise to make 

 a trial in the Eoyal Botanic Garden, Edinburgh. As matter of fact 

 the plant can be struck from cuttings — from internodal more rapidly, 

 perhaps, than from nodal. What is the obstacle elsewhere I have 

 yet to discover. 



Shortly before this I had learned from the Chief of the Bureau of 

 Plant Industry of the United States Department of Agriculture that 

 propagation of bamboos by cuttings had not been successful, although 

 their ready increase by such a method would have a deep bearing on 

 their distribution in America. Yet bamboos, like other monocotylous 

 plants of similar growth-form, can be readily increased by cuttings. 

 (Fig. 149.) 



I mention these incidents for the purpose of showing that the idea 

 underlying them — certain plants cannot be propagated by cuttings — is 

 not confined to amateur gardeners, and also by way of explaining why 

 1 have selected as my theme the subject indicated by the title. 



I believe the statement in my text is wrong. I believe that all 

 plants can be propagated vegetatively by cuttings — some easily, some 

 with more or less difficulty ; and, therefore, in view of the widely spread 

 impression to the contrary, I think it is worth while to endeavour to 

 remove the misconception. No more appropriate opportunity could 



