216 Principles of Plant Culture. 



close contact with the stems, and no leaves of the cut- 

 tings should be covered. Since roots cannot form with- 

 out oxygen, the bed must not be so freely watered as 

 to exclude all air. Transpiration should be reduced by 

 sheltering the cuttings from the direct rays of the sun. 

 Movable screens used during sunshine only, are prefer- 

 able to whitening the glass, which causes too much shade 

 when the sun is not shining. 



Damping off, a much-dreaded disease causing cut- 

 tings to ret at the surface of the bed, is promoted by 

 excessive heat, over-watering, or insufficient 

 light or air ; also by decomposing organic mat- 

 ter in the material 

 of the bed. Affected 

 I cuttings should be 

 promptly removed 

 and the trouble cor- 

 rected. 



379. Green Cut- 

 tings should be Pot- 



^^. ^. Cutting of chrysanthe- .', ~ 



mum. ted as Soon as Roots 



FIG. 102. Rooted cutting of col- 



eus. (Both after Bailey.) Form, which may be 



detected by their foliage assuming a bright color. They 

 should first be placed in small pots, and until they have 

 commenced growth in these, should be treated pre- 

 cisely as before they were potted. 



Propagation by green cuttings includes three divi- 

 sions, of which the requirements differ in some respects, 

 viz., propagation by cuttings of herbaceous plants, of 

 woody plants and of the leaf or parts of the leaf (leaf 

 cuttings} . 



