46 FAMILIAR TREES 



nothing in nature but an aged Holly-hock or a 

 gigantic Brussels-sprout. In this pruning the cut 

 ends are often carelessly made, so that wet-rot 

 and decay eat from them into the centre of the 

 stem. Neglect of broken or pruned branches affords 

 a lodgment to the spores of the Shelf-fungi {Poly'- 

 porvJ), the spawn of which then spreads throughout 

 the stem, producing a zone of touchwood which any 

 casual wind-gust may snap. Even when completely 

 hoUow, a battered veteran will long retain enough 

 vitality in its mere shell to put forth some leaves 

 each year. 



The timber of the Elm is too useful to be thus 

 wantonly destroyed. The whole log can be used, the 

 lighter sapwood being as durable as the brown heart, 

 and when kept perfectly dry or completely under 

 water it is peculiarly imperishable. Hollowed Elm 

 logs were formerly almost exclusively used for water- 

 pipes, which are often disinterred even now in the 

 older parts of London, and the wood is still employed 

 for ships' pumps, keels, and bilge-boards, as well as 

 ^for chairs and furniture. When alternately wet and 

 dry it decays rapidly ; and thus, in the use to which 

 the greatest quantity is now put, to form our last 

 resting-places on ea;rth, it soon returns our dust to 

 that whence we were taken. 



The Elm is so variable in the degree of corkiness 

 of the stem and branches, the smoothness or downi- 

 ness of the young twigs, and the size of the leaf, that 

 we can hardly avoid considering Uhnus surculosa 

 as rather a group of allied forms than as a single 

 species. Among, the recognised varieties of this group 



