212 SYLVAN WINTER. 



not distantly related to the Oak. Here is a 

 group of these hard woods'* which includes the 

 species just indicated the natural order Cupu- 

 liferce comprising about 400 species, and compre- 

 hending three tribes. Of these, Betulece include 

 the Birches and the Alders ; Corylece the Hazels, 

 the Hornbeams, and the Ironwoods ; and Qwercinece 

 the Oaks, Beeches, and Chestnuts. There are two 

 species of Ironwood, one belonging to the genus 

 Ostrya and one to Olneya. The most valuable of 

 the former, having regard to the quality of its 

 wood, is Ostrya virginica, the other is Olneya 

 tesota. 



It will hardly be expected that the Ivy (Hedera 

 helix) could produce any wood of service, and it 

 is an exception to find this climbing tree of 

 sufficient size to contain a timber stem ; yet there 

 is a use made of its wood when of sufficient size 

 that may be new to many people. It is not hard, 

 though slow-growing, and it is, moreover, porous. 

 It is therefore used by being cut into thin slices 

 for filtering liquids. The wood of large roots is 

 also sometimes made into ' strops ' for sharpen- 

 ing knives. 



