206 Principles of Plant Culture. 



With very few exceptions, of which the greenhouse 

 sinilax * is one, cuttings of the succulent growth of the 

 stem, with a certain amount of healthy leaf surface in- 

 tact, will develop roots in all plants, under proper condi- 

 tions of humidity and temperature; hence propagation 

 from green cuttings is a very common and expeditious 

 method of multiplying plants. The healthy leaf surface, 

 capable of preparing food, is a very important part of a 

 green cutting, because the stem is less abundantly sup- 

 plied with reserve food during the growth period than 

 during the dormant period (185). 



Since the presence of leaf surface upon the cutting 

 greatly promotes transpiration (75), propagation from 

 green cuttings is scarcely practicable in the open air. 

 Bottom heat (362), with a comparatively low air temper- 

 ature, is especially important with green cuttings, in 

 order that the food prepared in the leaves may be de- 

 voted to the formation of roots. A small leaf surface on 

 the cutting is generally preferable to a larger one; in 

 many plants, a portion of a single leaf is sufficient. The 

 leaf surface should in no case be permitted to wilt, hence 

 the cuttings should generally be sprinkled with water as 

 soon as made. 



378. Especial Care is Necessary in Propagating plants 

 from Green Cuttings. In planting the cuttings, the ma- 

 terial of the propagating bed should be put in close contact 

 with the stems, and no leaves of the cuttings should be 

 covered. Since roots cannot form without oxygen, the 

 bed must not be so freely watered as to exclude all air. 

 Transpiration should be reduced by sheltering the cut- 



* Asparagus meteloides. 



