214 The Natural System of Botany. 



opening, at the same time, by their face, so as to let the seed 

 drop out. This is caused by the styles contracting from dry- 

 ness, and shortening ; they stick so close together at the points, 

 that they cannot separate there, and so they actually pu u up 

 the ovary by the roots, and then roll up upon themselves as 

 though frightened at what they had done." 



The Geraniaceae are extensively diffused over the globe. 

 The chief residence of the cultivated Pelargoniums is at the 

 Cape of Good Hope. By cultivation, and hybridizing, many 

 new varieties have been raised. The effect of hybridizing f s 

 to produce in a single individual the characters of two others. 

 Thus, if the pollen of a plant with blue flowers is placed upon 

 the stigma of one with red flowers, the seed will produce a 

 plant with purple flowers ; or, if a sort with large, coarse flow- 

 ers, be intermixed with one which has small, neat flowers, the 

 result will be a large and neat flower. The Pelargoniums 

 intermix very readily, and this is the reason of the numerous 

 varieties, and improved kinds. This intermixture, however, 

 it must be remembered, will only be effectual among varieties 

 of the same species, or among species which are very nearly 

 related to each other. 



The plants of this order possess an astringent principle, 

 which, in our common spotted Geranium, is so powerful as to 

 make its roots a valuable medicinal article. They also have 

 an aromatic, resinous principle, which causes the dry stem 

 of one species to emit when burning a most agreeable odor. 



