576 WEEDS : GENERAL 



April or May, and frequently contain more than one embryo. 

 The root arising from the embryo easily penetrates the bark of 

 an apple tree, and dissolves its way down to the young wood. 

 After a year or two lateral roots arise on the primary root, and 

 run between the wood and bark parallel to the surface of the 

 branch. They are readily seen as soft bright green strands when 

 the bark is removed. From the upper side of these lateral roots 

 adventitious buds arise and push their way outwards, ultimately 

 becoming young mistletoe plants, while on the lower side short 

 roots or sinkers are sent down to the young wood to absorb 

 water and mineral substances, which have been taken up from the 

 soil by the roots of the' apple tree. Growth is at first very slow, 

 a three-year-old plant being only an inch or so high. After the 

 fourth year, when the root-system is established, the mistletoe 

 grows more vigorously. 



To eradicate and diminish the attack on the trees all the 

 berry-bearing (female) plants should be cut out of the branches 

 while still young, as it is then easy to remove the plants com- 

 pletely, as the joots are not strongly developed. 



Breaking or cutting off the stem is of no use, as it only stimu- 

 lates the formation of more adventitious buds on the roots, and 

 these come above the bark as a fresh crop of shoots. Where the 

 parasite is strongly established nothing but sawing off the branch 

 will eradicate it. 



Yellow Rattle {Rhinanthus Crista-galli L.), Eyebright {Euph- 

 rasia officinalis L.), and Red Rattle {Fedicularis sylvatica L.) 

 met with in meadows, and Lousewort {Fedicularis palustris L.) 

 occurring on marshy ground, are common parasites, which live 

 partially upon substances obtained by means of haustoria from 

 the roots of other plants. 



e. Another but indirect way in which weeds cause injury is 

 by harbouring and feeding insect-pests of various kinds. For 

 example, the turnip-flea feeds upon charlock and other crucifer- 

 ous weeds, and skips from these to the turnip crop. The bean- 



