146 



FAMILIES OF FLOWEEING PLANTS 



berries are pungent and aromatic, and are sometimes chewed as a rem- 

 edy for toothache. The trees of the Brazilian genus Esenbeckia have 

 bark possessing bitter and tonic properties. 



The orange and orange-like plants have frequently been classed as 

 a distinct family, but are now usually included in the Rutaceae. There 

 are numerous genera in this tribe, almost exclusively East Indian in 

 origin, but frequently cultivated. All are distinguished by the familiar 

 pulpy fruit. The orange, lemon, lime and shaddock all belong to the 

 genus Citrus. Mention should be made of one other American ruta- 

 ceous tree, the hop trefoil {Ptelea), distinguished by its trifoliate leaves 

 and dry, winged fruit. 



Family Simarubaceae. Ailanthus Family. Contains about 27 

 genera and 150 species, natives of tropical regions. They are trees or 

 shrubs with bitter bark, distinguished from the preceding family mainly 

 by the absence of dots on the foliage. The flowers are regular, either 



perfect or dioecious, 3-5-parted, the petals 

 borne on a disk. The fruit is various. 



Our only North American representa- 

 tives of this family are the ailanthus or "tree- 

 of-heaven," a well-known shade tree exten- 

 sively naturalized from Asia, and an indig- 

 enous species of Simarouba, on the Keys of 

 south Florida. Various South American 

 species of the genus yield valuable medi- 

 cines. Quassia is the product of several 

 trees belonging to this family, but is princi- 

 pally derived from Simarouba amara (Fig. 

 128, no. 1). 



Family Burseraceae. Terebinth Fam- 

 ily. Contains 16 genera and about 300 species, natives exclusively of 

 tropical Asia, Africa and America. They are forest trees of high value 

 as resin and balsam bearing plants. Thus mj^rrh is the product of 

 Commiphora Ahyssinica, and bdellium is derived from C. Africana. 

 The resin known as olibanum, which is supposed to have been the 

 frankincense of the ancients, comes from the Arabian Boswellia Carteri. 

 Various gums are yielded by Bursera, the only genus which penetrates 

 the Florida peninsula. The fruits of Canarium are edible. The Bur- 

 seraceae as a whole have no good characters distinguishing them from 

 the two preceding families, except that the husk of the fruit splits into 

 valve-Kke segments. A section of the flower of Boswellia Carteri, show- 

 ing structure, is seen in Fig. 128, no. 2. 



Family Meliaceae. Melia Family. Contains about 40 genera and 

 200 species. They are trees or shrubs differing from most of the fam- 



Fig. 128. Cross-section of flow- 

 ers, enlarged. i. Quassia (Sima- 

 rouba officinalis) . 2. Boswellia Car- 

 teri. 3. Mahogany (S^vietenia Ma- 

 hogoni). Redrawn from Engler. 



