72 



DOMESTIC BOTANY. 



It is, however, known that on plants of near relation- 

 ship coming into contiguity, they, like the different races 

 of mankind, commingle and produce intermediate forms, 

 which in many cases assume permanency. If their history 

 were unknown they might be viewed as original species, 

 but to all such forms the term hybrid^ is applied. 



Many plants presumed to be representatives of one 

 species often present different appearances, such as some 

 being tall, others dwarfish, or with variously formed leaves, 

 as broad, narrow, smooth, hairy, variegated, &c. Such dif- 

 ferences, called varieties, are mainly due to the situation 

 and nature of the climate and soil in which they grow, but 

 in the course of ages become inherent in their constitu- 

 tion. Thus the towering tree of the forest may be seen 

 on the rocky cliff as a dwarf shrub, being in that form 

 as much at home there as its congener in the richest 

 forest land. The birch, oak, fir, &c., are examples in this 

 country. In New Zealand and Terra- del-fuego, the lofty 

 trees of the plains are represented in elevated regions in 

 the form of low bushy shrubs. But those species that 

 have long been under the fostering care of man, have by 

 art and cultivation entirely changed their original nature, 

 and by such means our best wheat, fruits, vegetables, and 

 showy flowers have been obtained. 



In many garden plants the varieties are so numerous 

 that the original parent cannot be traced. In other 

 cases, parts of the same plants are so different from each 

 other, that, when separated unknown to the botanist, 

 they have been described as distinct species. This, with 

 the differences brought about by climate, and the in- 



* Tor particulars on this point, see Darwin's work on " Animals 

 and Plants under Domestication." 



