36o BOTANY AND PHARMACOGNOSY. 



Styrax Benzoin is a medium-sized tree with long, ovate, 

 acuminate leaves which are very hairy on the under surface. The 

 flowers occur in terminal racemes, and are silvery white on the 

 outer surface and reddish-brown on the inner surface. The bal- 

 samic resin yielded by this plant is official as benzoin (p. 672). 



HI. ORDER GENTIANALES OR CONTORTS. 



The plants of this order have opposite leaves, the flowers are 

 regular and the gynaecium consists of two separate carpels. The 

 order includes five families all of which furnish medicinal plants. 

 . a. OLEACE^ OR OLIVE FAMILY.— This family is 

 chiefly of interest because of the olive and manna trees. 



The olive tree (Olea enropwa) is indigenous to the Orient and 

 is now cultivated extensively in Southern Europe, Northern 

 Africa, the islands of the Mediterranean, tropical America, 

 including the Southern United States, and in California. The 

 leaves are narrow-lanceolate, entire, coriaceous and evergreen. 

 The flowers are small, white, diandrous and in axillary racemes. 

 The fruit is a drupe, the sarcocarp of which is rich in a fixed 

 oil known as olive oil. The oil is obtained by expression, and 

 is official. Depending upon the character of the fruits and 

 the amount of oil which they yield, over forty varieties are recog- 

 nized. The trees attain a great age, some of them being known 

 to be over a thousand years old. 



Fraximis Or mis is a tree resembling the ash, with 7-foliate 

 leaves, and polygamous flowers occurring in compound racemes. 

 The fruit is a flat samara with the wing at the apex. The sac- 

 charine exudation from this plant is official as manna (p. 649). 



The white ash (Fra.riniis americana) is a valuable tree on 

 account of the timber which it yields. The bark contains a bitter 

 glucoside, fraxin, the solutions of which are fluorescent; a bitter 

 substance, fraxetin ; an ethereal oil of a butter-like consistency, and 

 tannin. Some of these principles are also found in other species 

 of Fraxinus growing in the United States and Europe. 



The bark of the fringe tree (Chionanthus virginica) of the 

 Southern United States, contains an intensely bitter glucosidal 

 principle, chionanthin, and possibly also saponin. 



