CLIMBING PLANTS AND PARASITES 51 



dodder in groping for new food lay hold of and suck 

 their own older shoots ! Fig. 32 shows one of our 

 scrub vines — the dodder laurel. 



11. Another plant that makes no food for itself is 

 the mushroom. Living on dead or dying roots and 

 bulbs, the mushroom needs no green leaf in order to 

 make food. Of still more interest to us is the " rust ' 

 in wheat and other plants. This is a minute plant 

 that lives on the wheat, and does no work for itself. 

 The rust on wheat alone is thought to cause a loss to 

 Australia of £2,000,000 a year. There is a common 

 orchid, too, that has no green leaves. This orchid, 

 which bears a spike of flowers with red spots, lives 

 largely on the roots of other plants. Just as the 

 wire-worm and the grub of the cockchafer live on 

 grass roots, so there are several plants that live on the 

 roots of other plants. 



12. How the gardener imitates Nature. The 

 idea of budding or grafting one kind of plant on 

 another kind of plant may have been got from the 

 mistletoe. Have you ever watched a gardener fasten- 

 ing the bud of one kind of rose — say the Bride, into 

 the bark of another kind of rose, say the Safranot f 

 If the budding be a success, he gets, in a year or two, 

 a Bride rose bush growing on Safranot roots.* In 

 the same way, we may get a peach tree to grow on a 

 plum tree root, if we think that the plum tree root is 

 better fitted for a particular soil.t 



Questions and Exercises. — 



(1) Why do the prickles on the rose and the bramble point 

 downwards ? 



* For budding and grafting see Chap. SXVI. 



t Peaches and apricots are sometimes grown on plum tree roots when 

 the soil is cold and wet. 



