376 OLACACE^;. 



in which it grows. Green Tea contains more essential oil and tannin than 

 Black Tea. The Green Teas include Twankay, Young Hyson, Hyson, 

 Gunpowder, and Imperial; while the Black include Bohea, Congou, 

 Souchong, Oolong, and Pekoe. The teas of certain districts, such as 

 Ankoi, have peculiar characters. In some instances teas are dyed by 

 means of Isatis indigotica; hi other cases, by means of Prussian blue 

 and gypsum. Perfume is communicated to teas by means of Oka 

 fragrans, Chloranthus inconspicuus, and Aglaia odorata. There is a 

 bitter principle in tea called theine, which may be procured by adding 

 a slight excess of acetate of lead to a decoction of tea, filtering hot, 

 evaporating, and subliming. According to Dr. Stenhouse, 



1 Ib. of Green Hyson Tea gave 72 grains pure white Theine, and 2 coloured 



= 74 grains or 1'05 p. c. 



8 oz. Black Congou gave 34'5 gr. pure, and 1-5 impure = 36 gr. or 1-02 p. c 

 6 oz. of Black Assam Tea yielded 36 gr. or T37 p. c. 

 1 Ib. of a cheap Green Tea, called Twankay, gave 69 gr. or 0'98 p. c. 



In 1846, the Imports of Tea into the United Kingdom were 



Black, about 43,000,000 Ibs. 



Green, about 13,000,000 



Total, 56,000,000 



An interesting account of the Tea plants, and the manufacture of Tea, 

 will be found in Fortune's " Travels in China," in Ball's " Account of 

 the Cultivation and Manufacture of Tea," Royle's "Illustrations of 

 Himalayan Botany," andhis "Productive Resourcesof India." Thegenus 

 Camellia is prized on account of its showy flowers. There are numer- 

 ous cultivated varieties of Camellia japonica, many of which can endure 

 the climate of Britain when trained on a wall with a southern exposure, 

 or slightly protected. In China, Camellia Sasanqua, or Sasanqua tea 

 is cultivated on account of its flowers, which are said to impart fra- 

 grance and flavour to other teas. Camellia oleifera yields a valuable oil. 

 794. Order 34. oiacace*e, the Olax Family. (Polypet. Hypog.} 

 Calyx small, gamosepalous, entire or toothed, often becoming finally 

 large and fleshy; aestivation imbricated. Petals 3-6, hypogynous, 

 free, or adhering in pairs by means of the stamens; estivation valvate. 

 Stamens hypogynous, some fertile, others sterile; the former 3-10, 

 alternate with the petals, the latter opposite to the petals; filaments 

 compressed; anthers innate, bilocular, with longitudinal dehiscence. 

 Ovary 1-3-4-celled; ovules 1-3, pendulous from a central placenta; 

 style filiform; stigma simple. Fruit fleshy, indehiscent, often sur- 

 rounded by the enlarged calyx, unilocular, monospermal. Seed ana- 

 tropal, pendulous; albumen copious, fleshy; embryo small, at the 

 base of the albumen. Trees or shrubs, with simple, alternate, exsti- 

 pulate leaves, which are, however, sometimes abortive. They are 



