THE ROOTS AND STEMS OF TREES 151 



The conversion of the aerial roots of tropical Figs 

 (banyan, &c.) and Aroids into stems is well known. The 

 same thing may sometimes be seen in European forest-trees, 

 e.g. in horse-chestnuts at Guisborough Abbey. 



Such examples as these make it clear that stems 

 can send down roots, and that roots can send up stems. 

 Botanists are not ignorant of these facts, and careful 

 writers point out that no absolute distinction can be drawn 

 between leaf, stem and root. 



The formation of new shoots from trunks which have 

 been felled may be seen in almost any timber-yard ; it 

 illustrates the store of available food which may be present 

 in the wood of a tree. Elm, poplar and willow are par- 

 ticularly ready to sprout after being felled. A large elm- 

 trunk will sometimes send out a multitude of young shoots, 

 which overlay the old bark with a cake of new wood 

 covering many square feet. Examples can be seen in 

 Burleigh Park and many other places. 



XXXI. HEDGE AND DITCH; A Summer 

 Term's Work for a School Form. 



THE HEDGE. 



The hedge that I have in my mind shows a good variety 

 of plants, though it is not richer than many others situated 

 in that part of Yorkshire where the magnesian limestone 

 underlies the soil. If I were a schoolmaster, and had 

 such a hedge near at hand, I should make it part of my 

 business to explore it with the boys. Before or during the 

 natural history work I should try to get the hedge and two 

 or three neighbouring fields surveyed. Among other 

 things every large tree should be set down on the map in 

 its proper place, and with its name. What practice in 

 elementary geometry and mensuration we should get out 

 of the survey ! What light the construction of our own 

 plan of a few well-known fields would throw upon the maps 



