Propagation by Cuttings. 209 



grafted plants are often covered with bell-jars. To 

 guard against sudden fluctuations in temperature, a 

 larger bell-jar is sometimes placed over a smaller one. 

 By means of a bell-jar with a tight- 

 fitting ground plate, evaporation 

 may be wholly prevented from cut- 

 tings or plants, if do- 

 sired. Propagating beds 

 are often covered with 

 glazed sash, in addition 

 to the glass roof of the 

 house, to assist in main- 

 taining a moist atmos- 

 phere about the cut- 

 tings (Fig. 96). 



For convenience, we 

 separate propagation by cuttings into two divisions, 

 viz., propagation by cuttings from dormant and from 

 active plants. The requirements of these two classes 

 differ in some respects. 



a Propagation by cuttings from dormant plants. 



370. The Time to Make the Cuttings. We have 

 seen that plant processes may not be wholly suspended 

 during the dormant period (176). This is true not 

 only of the plant as a whole, but also of detached parts 

 of the plant, if they are protected from evaporation. 

 If cuttings are taken from a plant in autumn and 

 stored during winter in a moist place of moderate tem- 

 perature, the cut surfaces will partially callus over 

 (72), and the formation of roots or buds may com- 

 mence before spring. 



FIG. 96. Propagating bed covered 

 with glazed sash. 



