124 SEEDS. 



(63) Guarana. 



A paste prepared from the seeds of Paullinia Cupana, 

 H. B. and K. (N.O. Sapindacese). 



The seeds of this plant are covered with a dark brown 

 seed-coat in which two distinct layers can be observed. The 

 outer consists of a single row of cells which are much 

 elongated radially and have thick brown walls ; in surface 

 view these cells are seen to have a very sinuous outline, and 

 also to vary considerably in size. 



The inner part of the seed-coat consists of parenchymatous 

 tissue composed either of stellate cells with large inter- 

 cellular spaces and slightly beaded walls or of polygonal 

 cells without intercellular spaces and with markedly beaded 

 walls. A few of the latter are thickened and lignified. 



The large arillus at the base of the seed is composed of 

 small polygonal isodiametric cells with pitted walls. 



The endosperm is made up of large rounded or polygonal 

 cells filled with gelatinised starch. Fragments of vessels and 

 of fibres from the raphe may also be found in the powder. 



The diagnostic characters of guarana are :- - 



(a) The conspiciwus cells of the epidermis. 



(b) The beaded and pitted jparenchymatous cells. 



(c) The endosperm cells filled with gelatinised starch. 



