12 THE USES OF PLANTS. 



scientific encouragement, in spite of the exertions of 

 Mr. John Smith, the Curator ; yet, even then, innumer- 

 able travellers in every corner of the globe were add- 

 ing rapidly to our knowledge. 



Many plants have been so long in cultivation, and 

 have been so altered thereby, that we no longer know 

 what was their wild original form. Such is the case 

 with Wheat (Triticum vulgare, L.), Oats (Avena saliva, 

 L.), and the Barleys (Hordewri). The cultivation of 

 other food-plants, such as Peas (Pisum sativum, L.), 

 Beans (Faba vulgaris, Moench.), Plums (Prunus 

 domestica, L.), and Apples (Pyrus Mains, L.), in this 

 country ; and of the Fig (Ficus Carica, L.), the Grape 

 (Vitis vinifera, L.) and the Indian Corn or Maize (Zea 

 Mays, L.), in other countries, may fairly be said to be 

 of prehistoric antiquity. So, too, with some other 

 plants not used for food, such as Flax(Lmum usitatis- 

 simum, L.), and Hemp (Cannabis sativa, L.), in the 

 Old World, Tobacco (Nicotiana rustica, L.), in the 

 New World, and Cotton (Gossypium] in both hemi- 

 spheres. Others, again, though generally employed in 

 the industrial arts for ages, can hardly be said to have 

 been cultivated till a comparatively recent period, if 

 at all. Such is the case of most timber-trees until 

 within the last two centuries, and of such tropical food- 

 plants as the Date Palm (Phoenix dactylifera, L.), and 

 the Banana (Mtisa sapientum, L.). 



The Indian expedition of Alexander the Great 

 and the wide-reaching conquests of the Roman 

 generals no doubt introduced many useful plants 

 into Europe. Our cornfields still bear witness, in 

 their weeds, to the wide area from which the Roman 



