1764 



A TEXTBOOK OF THEORETICAL BOTANY 



and a minute epigynous perianth. The ovary is bilocular. The fruit is a 

 one-seeded nut with a three-lobed leafy wing which is derived from the 

 growth of the bract and two bracteoles, which form the side lobes. 



Corylus avellana is the Hazel and is a shrubby plant often increased by 

 suckers. It produces monoecious catkins, the male (Fig. 1647) ripening 

 early, before the leaves. The females (Fig. 1648) are much smaller and are 

 recognizable only by the bright red stigmas. Pollination is anemophilous 



Fig. 1647. — Corylus avellana. Hazel. 

 Male catkins open and shedding 

 pollen. 



Fig. 1648. — Corylus avellaim. 

 Female catkin with protrud- 

 ing stigmas. 



but the chances of fertilization are probably enhanced by the fact that it 

 occurs when the branches are bare of leaves. The nuts, which are some- 

 times referred to as Cob-nuts or Filberts, are edible and the plants have been 

 cultivated from early times. The wood is elastic and is used for many 

 agricultural purposes, for fixing down thatch, and for the construction of 

 primitive implements. Hazel twigs are especially popular with water 

 diviners in searching for water. 



In the Betuloideae the two common genera are both represented in the 

 British Flora. B. verrucosa is the Common Birch while B. nana, the 

 Mountain Birch, is a low shrub common in north temperate regions. 

 Birch wood is tough and is much used in the making of wooden shoes. An 

 oil prepared from the bark is used for tanning Russian leather to give it a 

 peculiar fragrance. The bark of B. papyracea was used for making native 

 Indian canoes in North America. 



