6i8 A TEXT-BOOK OF BOTANY. 



The fresh leaves of Thea do not have the properties which 

 characterize the commercial article, the aroma and other qualities 

 being developed after special treatment. Two general classes of 

 tea are found in commerce, these depending on the mode of treat- 

 ment. Those which are rapidly dried by means of artificial heat 

 constitute Green tea. The leaves which are slowly dried, per- 

 mitting fermentation to set in, furnish Black tea. Tea leaves 

 contain 1.5 to 3.5 per cent, of caffeine; theobromine and the- 

 ophylline (an isomer of theobromine) ; 10 to 20 per cent, of gallo- 

 tannic acid ; quercitrin, and a volatile oil containing, among other 

 components, methyl salicylate. The seeds contain about 30 per 

 cent, of fixed oil, i per cent, of caffeine, and saponin. The leaves 

 furnish one of the sources of the official caffeine. Saponin is 

 found in the seeds of Thea Sasanqua of China and Japan. Two 

 saponin-like substances (assamin and assaminic acid) are found 

 in the seeds of Thea assaniica. The flowers of T. Sasanqua are 

 used in China and Japan to flavor teas. The flowers and leaves 

 of Thea Kissi are used as an insecticide. The red colored sap of 

 Laplacea Hcematoxylon of New Granada is used in medicine. 



d. GUTTIFER^ OR GAMBOGE FAMILY.— The plants 

 are principally shrubs and trees of the Tropics, that is, if we 

 exclude the Hypericacese which are now put in a group by them- 

 selves. 



Garcinia Hanburyi is a tree with ovate, petiolate, coriaceous, 

 opposite leaves. The flowers are small, yellow, dioecious, occur- 

 ring in small clusters in the axils of the leaves. The fruit is a 

 pome-like berry, with a papery endocarp and an oily sarcocarp, 

 and 3 or 4 seeds, i in each loculus (Fig. 340). The trees are 

 chiefly valued on account of the gum-resin known as gamboge 

 which they contain. 



A resin used in making plasters is obtained from Calophyllum 

 brasiliense of Brazil. Balsams resembling Copaiba have been 

 obtained from Calophyllum Calaha of the West Indies. Balsams 

 known as Tacamahac are also derived from the following plants : 

 Bourbon Tacamahac from Calophyllum TaeamaJiaea, India Taca- 

 mahac from C apetalum and Brazilian Tacamahac from Rhcedia 

 Madruno. Balsams are also obtained from Caraipa grandiHora 



