198 FAMILIES OF FLOWEEING PLANTS 



the tropics, with a few forms extending into temj)erate lands. North 

 America, for instance, has but 4 genera and about a dozen species, and 

 these mostly confined to Florida. Australia possesses a number of pecu- 

 liar and striking genera, among them Eucalyptus, a genus embracing 

 about 160 species. They are usually tall trees, with narrow, leathery 

 leaves. One species, the white peppermint-tree or giant gum-tree {E. 

 amygdalina), is, according to the late Baron von Mueller, probably the 

 loftiest tree on the globe, attaining a height of 475 feet and a diameter 

 of 15 feet. This and many other species of Eucalyptus are of the greatest 

 economic importance, furnishing timber for a wdde variety of uses, as well 

 as various oils, resins, acids, tannin, etc. Eucalyptus is thought to be 

 of value in malarial regions in absorbing or warding off noxious emana- 

 tions ; hence, several are known as fever trees. Some 70 or 80 species of 

 Eucalyptus have been more or less extensively introduced on the Pacific 

 Coast, but only a few, such as E. polyanthema, E. globulus and E. rohusta, 

 are most abundant ; all are of rapid growth. 



Among the many economic products of this family we may mention 

 allspice or pimento, the product of Eugenia Pimenta or Pim€)ita 

 ojicinalis, a tree of Mexico and the West Indies . Allspice consists of the 

 fruits gathered before they are quite ripe and dried in the sun. The 

 cloves of commerce are the dried flower buds of Eugenia caryopliylla, a 

 tree originally of the Moluccas, but now widely cultivated in the East and 

 West Indies. The guava tree (Psidium Guajava) of tropical America 

 produces the well-known guava fruits of tropical countries. The myrtle 

 of the ancients is Myrtus communis, a tree of the Mediterranean region. 



Family Melastomaceae. Melastoma Family. This is also an 



Fig 174. The Yellow Deer-grass {Rhexia lutea.) 



immense family, which embraces about 150 genera and 2500 species. They 

 are herbs, shrubs or trees, with mainly opposite 3-9-ribbed leaves with- 



