GRAFTAC.K GKXKKAL COXSIOKRATIONS 



147 



it is always sharply defined from the 

 remaining portion (xylem, 203) by a 

 layer of cambium. The inner bark is 

 derived from the phloem, the wood 

 from the xylem. The elaborated plant 

 food from the leaves passes down and 

 is distributed by the phloem. 

 F SPV T FnTR Y F E F A s R 203 ' X y lem or wood y Portion of a 



SPY BUDDED TREES ,-., , 11 1*1 , 



fibro-vascular bundle which contains 



A, stem cut at 15 inches 

 and grafted. B, Uncut. 



working checks growth. 

 It also delays bearing. 



the larger continuous air- 

 holding vessels and the walls 

 of whose cells are often 

 thickened and lignified. The 

 xylem is separated from the 

 phloem (202) by the cam- 

 bium, when there is any, and 

 it usually occupies the side 

 of the bundle toward the 

 center of the stem. \Yater 

 with the mineral compounds 

 in solution passes up 

 through the xylem to the 

 leaves. 



204. Limits of graftage. 

 Theoretically botanists and 

 nurserymen have limited 

 graftage to the exogens, 

 plants which have a cam- 

 bium layer in a definite re- 

 gion beneath a bark layer; 

 for the process depends upon 



the intimate Union of Trees so handled have usually been 



this layer between stock have Farge'bunches^of sh r orrfib e rous a roots 

 and cion. Of the 151 a e t y ed are almost sure to grow when so 



FIG. 131 BURLAPPED FOR 

 SHIPMENT 



