Teachers' Leaflet. 



543 



Ohio Buckeye. Horse-chestmit foliage and Hoivers. 



a thrifty tree with the sky at its back, it seems a solid mass of dark, rich green 

 with but few chinks of light. 



Note the brown bark of the trunk and its tendency to break into plates. 

 Younger branches are lighter or grayish-brown. In the buckeyes, young bark has a 

 yellowish tinge. Although the lower branches are large and sturdy, it does not 

 divide out in the fan-like way of the maple, but builds its pyramid by lifting its 

 trunk well toward its apex. 



LESSON XVII. 



the leaves. 



What they do for the tree; What they do for mankind. 



Preliminary work. — Before taking up the horse-chestnut leaf in particular, 

 give a short lesson on leaves in general ; that it is by the action of the green leaf- 

 cells that trees and all other plants are able to assimilate their food. Many tons 

 of " crude sap," as the food-laden moisture is called, which is gathered by the 

 roots from the soil, are carried up to the leaves, where much of it is given off in 

 transpiration, thus moistening, cooling and purifying the air. But the mineral food 

 which is carried is retained in the green leaf laboratories, is combined with the 

 gases in the atmosphere, and by the power of the sun's light and heat is trans- 

 formed largely into starch, which is the only form of plant-food available for 

 the making of new growth. All green leaves are starch factories and it is through 

 the working of this miracle, year by year, that the whole world is fed. 



