112 PLANT rUOPAGATlON 



is expected the cuttings are sometimes started in heated propa- 

 gating beds in fall so plants may be ready for sale in spring. 

 In the South they are often made in spring and planted in the open. 



Pear, apple, cherry and peach root cuttings may be 

 grown in frames with bottom heat, but tliis method has 

 never been very popular with nurserymen because graft- 

 age (192) is considered more economical. 



Root cuttings are open to the objection that they do 

 not always transmit variegation 

 though they do perpetuate the va- 

 ^"^ ^/i"^?" riety otherwise. It must also be re- 



membered that the root will propa- 

 gate its variety ; that is, if roots of 

 a grafted plant be selected, those 



FIG. 99-CUTT,NG ^^'^^^ ^""^^ '^<;l°^ the tinioU will 



READY FOR BURYING produce seedhug-stock plants, 

 while those above that point will 

 grow plants of the cion variety. 



163. A sport or bud variation is a plant or plant part, 

 as a twig, which unexpectedly shows a character differ- 

 ent from that of the variety or species or the balance of 

 the plant. Usually this character cannot be reproduced 

 by seed but is almost always propagated asexually. Even 

 then it is still called a sport. The term is not commonly 

 applied to monstrosities or deformities, but to more or 

 less attractive and apparently normal characters, as 

 doubling of flowers on single-flowered plants, variega- 

 tion and other changes of the color on green plants, etc. 

 Bud variations may be the starting point of new varieties 

 or of reversions to earlier forms. 



1C4. Tubers and tuber cuttings, because of their food 

 content, can live long after growth starts before the new 

 plants may be able to take food from the soil. In potato 

 plant formation the eye sends a shoot through the soil to air 

 and light. Then roots begin to form near the base of the 

 shoot. These roots secure food thoup;h the plantlet con- 

 tinues to draw upon the food stored in the tuber. In 



