THE ROOT 27 



7. If the water were always at the same level, the 

 plants best suited for each place would always be 

 found in that place ; but since the water level often 

 changes, there is a constant struggle between the 

 various kinds of plants to get the soil that suits them. 

 Those that are half of the water and half of the land 

 will march in towards the water in years of drought ; 

 but are driven back to the bank when the water rises 

 again. In times not yet long past, great parts of the 

 earth were marshy and undrained ; and therefore we 

 need not wonder that so many plants are at home in 

 water or in sodden ground. But nearly all the 

 higher plants and nearly all the plants of use to 

 man, need well-drained soil, loose and open to the air. 



Problems and Exercises : — 



(1) Place a seedling, gro^vll in a pot, on its side, in order to show 

 that the green shoot persists in growing upwards. 



(2) In studying the downward pull of roots, examine the runners 

 of strawberries and the wrinkles in a parsnip root. 



(3) In the carrot, rhubarb, and dock, note that the leaves are 

 arranged so as to drain the rain and dew towards the centre. 

 Shew how the root plan corresponds. 



(4) It is often useless in watering an old tree to throw water at 

 the foot of the stem. Give the reason. 



(5) When a gardener, in taking up a tree, loses half the roots, 

 why must he also cut back the branches to the same extent ? 



(6) Explain why well-drained land yields much larger and iiner 

 crops than undrained land. Describe the appearance of wheat 

 plants on low, wet parts of the field. 



(7) The willow is sometimes planted in damp, undrained soil to 

 help to keep the ground dry. Explain how some trees can thrive 

 in soil like this. 



Composition Exercise : — Tell the adventures of a root as it 

 travels in search of root-food. 



Drawing Exercise :--Make drawing of a tree whose branches 

 hang umbrella-like over the earth ; and shew by faint lines below 

 the surface where the feeding roots are placed. 



