PROPAGATION BY MEANS OF CUTTINGS 107 



portions of stems are on record. Chips from a tree trunk 

 have been known to produce plants, and the olive is readily 

 increased by knots or excrescences formed upon the trunks of 

 old trees. These excrescences occur in many plants, and are 

 known as knaurs. They are often abundant about the base 

 of large plane-trees, but they are not often used for purposes 

 of propagation. Whole trunks will sometimes grow after 

 having been cut for many months, especially of such plants as 

 cactuses, many euphorbias and yuccas. Sections of these 

 spongy trunks will grow, also. Truncheons of cycad trunks 

 and tree ferns may also give rise to plants. Even saw-logs of 

 common trees, as elm and ash, will sprout while in the "boom," 

 or water. 



(2) Green-wood cuttings. 



Cuttings of green wood are more commonly employed than 

 those from the mature dormant wood, as they "strike" more 

 quickly, they can be handled under glass in winter, and more 

 species can be propagated by them than by hardwood cuttings. 



Green-wood cuttings are of two kinds as respects maturity : 

 those taken from soft and still growing parts, herbaceous in 

 character; those made of shoots that have practically ceased 

 growing and are woody. The shoots are spoken of as "wood" 

 by gardeners, whether actually woody or not ; this has become 

 a special technical term. "Slips" are green-wood cuttings, but 

 the term is often restricted to those made by pulling or "slip- 

 ping" off a small side-shoot, and it is commonly applied to 

 the multiplication of plants in window-gardens. All soft- 

 wooded plants and many ornamental shrubs are increased by 

 green cuttings of one kind or another. House plants, as gera- 

 niums, coleuses, carnations, fuchsias, are grown from the soft 

 young wood, and many harder wooded plants are grown in 

 the same way. Sometimes true hardwood is used, as in 

 camellia and azalea. 



