1740 A TEXTBOOK OF THEORETICAL BOTANY 



cultivated in the Middle and Far East and used in the preparation of 

 Betel Pepper. P. methysticum is used in preparing the drink, Kava. Pepper 

 Oil or Piperonal is the source of synthetic heliotrope essence. 



URTICALES 



The Urticales are Archichlamydeae in which the flowers are usually 

 small and inconspicuous and are normally monoecious. The perianth is 

 hypogynous and often greenish in colour, consisting of either four or five 

 more or less united segments. The stamens are arranged opposite the 

 perianth segments and are equal in number to them. The ovary is made up 

 of either one or two carpels but is always unilocular and contains a single 

 ovule. The fruit is either a drupe, a samara or a nut containing one seed. 

 The embryo either occupies the whole of the seed or a fleshy or oily endo- 

 sperm may be present. 



Pollination is usually anemophilous or occasionally entomophilous. 



The majority of the members of this order are trees, though shrubs 

 and herbs also occur. They normally possess simple, alternate, leaves, 

 while the inflorescences are generally cymose. 



The limits of this order are clearly defined and most authorities agree 

 which families should be included in it. Both Flutchinson and Rendle 

 place the following families in the order: Ulmaceae, Urticaceae, Moraceae, 

 Cannabinaceae and Eucommiaceae. Though the families are poorly repre- 

 sented in the British Flora we shall have to consider each in some detail 

 on account of the economic importance of so many of their members. 



The Ulmaceae are mostly trees, though in two genera some species 

 are only bushes. Included in this family is Ulmiis, the Elm, which grows 



Fig. i6i8. — Ulmiis montana (U. glabra). Inflorescences 

 in early spring. 



into a large tree reaching a height of up to 150 ft. The leaves are simple, 

 oval-shaped, asymmetrical and arranged alternately in two rows up the 



