134 COMPOUND ORGANS OF PLANTS. 



Fig. 41. 



Raffles in the forests of Sumatra, in the year 1818, growing on 

 the stems of the Cissus augustifolia, a kind of climbing plant or 

 grape-vine. In the bud state this flower is nearly a foot in 

 diameter, and when fully expanded, nine feet in circumference 

 and three feet over from the tip of one petal to that of another. 

 Its substance is about half an inch thick, and the whole plant 

 weighs fifteen pounds. Its color is light orange mottled with 

 yellowish-white, and like other parasites, it derives its nutri- 

 ment from the tree on which it is found. A few other species 

 of less gigantic size have been discovered in the other islands of 

 the Eastern archipelago. 



Structurally, the petals or leaves of the corolla are composed 

 of cellular and vascular tissue, the latter consisting of spiral 

 vessels and delicate tubes. The color of the petals is produced 

 by the refined and splendidly colored juices elaborated from the 

 sap by the walls of the cells which form their tissue or substance. 

 This fact is easily verified by submitting to microscopic exami- 

 nation a fragment of the petal of a rose or of a camellia, when 

 it will be seen that the color does not exist in the walls of the 

 cells of the petal, but it is the result of the colored fluids with 

 which the cells are filled. 



