PROPAGATION OF PLANTS. 105 



Its life cannot be long continued, unless these correspond 

 with each other. A cutting, from the lack of roots, absorbs 

 feebly from the soil ; hence evaporation must be diminished 

 to correspond, and the base of the cutting must be in con- 

 tact with a substance more or less humid. Evaporation 

 is diminished by planting in a northern exposure, shading, 

 the use of bell-glasses, etc. The more herbaceous or im- 

 mature a cutting may be, the greater care is required to 

 protect it from excessive evaporation. 



Cuttings of hardy deciduous trees and shrubs should 

 be taken off after the leaves fall, or before the sap rises in 

 the spring. Those that strike readily in the open ground 

 in mild climates may be planted out to form the callus, 

 and be ready to enter into growth with the opening spring. 

 In more northern climates they may be prepared for plant- 

 ing, and stored in moistened moss or damp earth, and 

 kept from frost. The callus will be forming, and they 

 will be ready to plant in early spring. GeneraUy, cuttings 

 should not be taken when the sap is in full flow, as moist- 

 ure is then rapidly evaporated and the cutting exhausted 

 before roots are formed. They should be taken when the 

 plant is dormant, or when a new shoot has been made 

 with leaves so fully formed and matured as to be in the 

 act of forming abundance of woody tissue. 



In selecting cuttings, they should come from healthy 

 plants, from shoots of average strength, well nourished, 

 but not over vigorous, as the latter are more quickly ex- 

 hausted when deprived of their usual supply of nourish- 

 ment. Horizontal branches growing near the ground, 

 especially those which recline upon it, have a greater ten- 

 dency to throw out roots. Upright shoots from near the 

 summit are generally, but not always, less likely to suc- 

 ceed. The willow and poplar strike freely from old wood, 

 and trunks of considerable size, if planted, will emit 

 roots, but of most trees the best plants are made from 

 well matured shoots of the current year's growth. In the 

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