CHAPTER IX. 

 WINTER CONDITION OF SHOOTS AND BUDS. 



107. A study of the winter habit of perennial plants shows 

 some very interesting adaptations of plants to meet the severe 

 conditions to which they are subjected during the season. The 

 spring and summer is the growing season. The new growth is 

 at first comparatively tender, with an abundance of water and a 

 comparatively small amount of cell wall or building material in 

 the shoots and leaves. In this condition vegetation is very sus- 

 ceptible to either extreme cold or extreme drought. This is 

 occasionally seen in our climate (temperate zone) when there is 

 an early, warm spring. The new shoots and leaves are developed 

 rapidly. They are full of water and the tissues are soft and 

 weak. When a severe frost follows it often works great injury 

 to the new vegetation, the new leaves and shoots of hardy trees 

 and shrubs being killed and drying up, presenting a very un- 

 sightly appearance. The same effect is sometimes produced in 

 some plants when a strong, dry wind continuing for several days 

 often withers up the leaves and shoots because of the excessive 

 loss of water under these conditions. 



108. If vegetation passes this critical period without 

 injury the natural processes of maturity and ripening of the parts 

 prepare the plants for the long, severe winter season. Different 

 plants prepare to meet this season in different ways. The an- 

 nuals, which form little wood or protecting bark, expend their 

 energy in the production and ripening of seed, and then the plant 

 dies. The seed, or fruit, possesses dry, hard walls, and the liv- 

 ing substance in the embryo passes into a condition in which there 

 is little danger from either dryness or extreme cold. In the case 

 of the perennial herbs, the annual shoot produces its seed, and 

 then dies to the ground, while the underground shoot or root is 



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