HOW PLANTS ARE MODIFIED 



15. Woody or ligneous plants are usually longer lived 

 than herbs. Those which remain low and produce several 

 or many similar shoots from the base are called shrubs, as 

 lilac, rose, elder, osier. Fig. 5. Low and thick shrubs are 

 bushes. Plants which produce one main trunk and a 

 more or less elevated head are trees. Fig. 6. 



16. PLANTS ARE MODIFIED BY THE CONDITIONS IN 

 WHICH THEY GROW.— In most plants, the size, form and 

 general appearance vary or change with the conditions in 

 which the plant groivs. That is, , 



there is no uniform or necessaij ,'"_''' h 



form into which plants shall grow "^^i^^^-^ , 



No two plants are exactly alike. 



Observe plants of the same kind 



and age, and see how they differ 



or vary. The farmer and gai 



dener can cause plants to be large 



or small of their kind, by chang 



ing the conditions or circumstan 



ces under which they grow, 



17. No two parts of the same 

 plant are exactly alike. No two 

 parts grow in the same conditions, 

 for one is nearer the main stem, 

 one nearer the light, and another 

 has more room. Try to find two 



leaves or two branches on the same plant which are exactly 

 alike. Fig. 7. 



18. Every plant makes an effort to propagate or to per- 

 petuate its kind; and as far as we can see, this is the end 

 for which the plant itself lives. The seed or spore is 

 the final product of the plant. 



19. Every plant, — and every part of a plant, — under- 

 goes vicissitudes. It has to adapt itself to the condi- 

 tions in which it lives. It contends for place in which to 



^i 



6. A tree. The weeping birch. 



