217 



In continuation, the lecturer proceeded to contrast the readi- 

 ness with Vvdiich can be propagated cuttings from soft-wooded 

 and hard-wooded plants. The difficulty met with in the case of 

 hard-wooded plants is explained by the fact that the absorption 

 of water is less easily effected than in the case of soft cuttings. 

 For other reasons, which are later referred to, resinous plants, 

 and those rich in latex may also be difficult subjects for propaga- 

 tion by cutiings. 



After pomting out the nature of the development of a dicotyle- 

 donous cutting, the question as to whether it is advisable to re- 

 move the leaves at the base of a cutting is referred to. It is 

 pointed out that the practice of leaving them has these advan- 

 tages : (a) the cutting is saved the healing of the wound caused 

 by their removal : ( b ) the lower leaves sunk in the soil may 

 root like the stem and aid, thereby, water absorption; (c) the 

 lov,-er leaves ^^■ill aid in the manufacture of food for the cuttings. 

 Another point considered was the fact that some plants propagate 

 far more readily if the cutting be made through an internode 

 than through a node, and vice versa. As an illustration. Clematis 

 cannot be propagated if nodal cuttings are used, whereas inter- 

 nodal cuttings may be "struck" within a fortnight. It is indicated 

 that an investigation of the causes of such dift'erences in cuttings 

 is one of the problems of propagation which vet remains to be 

 solved. 



Alluding again to callus formation, the interesting and ex- 

 tremely important featm^e was noted that, however difficult it 

 may be for a cutting to strike, yet once callus is produced, root 

 development can always be stimulated by paring this callus. 



After referring to the importance of the size of cuttings illus- 

 trated by the fact that small cuttings of hard wood plants ger- 

 minate quicker than large ones, the lecturer dwelt upon the sig- 

 nificance of resin in relation to propagation. When, for instance, 

 cuttings are taken from coniferous trees, the shoots instead of 

 producing callus, generallv excrete resin. This flows out copious- 

 ly over the surface, covering it effectively with a hard skin, there- 

 by constituting a hindrance to the exit of young rootlets. It is 

 necessary not only to remove this resin but to check its exudation. 

 This can be done by plunging the cut end of the cutting in nearly 

 boiling water. The cut resin canals are thus sealed and doubtless 

 at the same time the heat stimulus promotes formation of callus. 

 Dicotyledonous plants with resinous and milky juice are in like 

 case with coniferous, and require to be treated after the same 

 fashion. 



The actual state of a shoot to be used for a cutting was another 

 point taken for consideration. A vigorously growing shoot re- 

 moved from a plant and at once placed in the nidus for propaga- 

 tion may fail to "strike."' Its vigor is probably too great. The 



