72 



FIELD AND WOODLAND PLANTS 



those of U. campestris, are irregularly doubly serrate, with hairs 

 on the prominent ribs of the under side, and are arranged in two 

 straight rows, one on each side of the twig. The flowers are very 

 similar to those of the Common Elm ; and the fruit is a broad 

 oblong or almost round samara, with the seed in the centre. Both 

 species are pollinated by the wind ; and, as is the case with wind- 

 pollinated flowers generally, the stamens protrude well out of the 

 flower, and produce abundance of pollen. 



The oak in flower. 



Four of our forest trees belong to the order Cupvliferce ; these 

 are the Oak, Beech, Hornbeam and Hazel. The first of them — the 

 Oak {Quercus Robur) — is easily recognised in the winter by its 

 deeply-furrowed, corky bark, its zigzag, spreading branches, and 

 the clusters of oval buds at the tips of the twigs. In summer it 

 may be known at once by the oval, sinuate leaves with blunt lobes. 

 The flowers of the Oak appear with the leaves'^in April or May ; 

 they are imperfect, but both male and female blossoms appear on 

 the same tree. The former are in slender, drooping, interrupted 

 catkins ; and each flower has ten stamens. The latter are in 

 clusters of a few only, and each separate flower is enclosed in a 



