MODE OF GROWTH OF WINTER-WHEAT. 47 



rior tobacco, poorer in albumen and nicotine, is pro- 

 duced if, instead of breaking the leaves oif in the field, 

 the plant with the leaves on it is cut down just above 

 the ground, and hung up to dry with the top down- 

 wards. The stem will, under these circumstances, con- 

 tinue to vegetate for a time, sending forth small shoots 

 which gradually turn in an upward direction and put 

 forth flower-buds. In these flower-buds the sulphureous 

 and nitrogenous constituents are collected from the 

 leaves, which lose these ingredients in the same propor- 

 tion, and are thereby improved in quality. 



Of the plants cultivated for the sake of their seed, 

 wheat holds the chief place. 



Winter-wheat is in its developement extremely like 

 a biennial plant. In the biennial turnip we see that 

 with the first leaves a corresponding number of root- 

 fibres are produced ; and that after the formation of the 

 leaf-top, the root begins to expand greatly in size and 

 extent, immediately after which the flower and seed- 

 stalk shoots forth. 



Yery soon after winter-wheat is sown, the young 

 plant puts forth the first leaves, which in the course of 

 winter and the early months of spring increase to a 

 tuft ; to all appearance the vegetation of the plant 

 seems to cease for weeks and months. When warm 

 weather comes, the plant puts forth a soft stem, several 

 feet high, furnished with leaves, and bearing at the top 

 an ear set with flower-buds in which, after flowering, 

 the seeds are formed. As the seed is developed, the 

 leaves from the bottom upwards turn yellow, and die 

 with the stem as the seed ripens. 



It cannot be doubted that while the growth of the 

 plant appears to have ceased before the time of shoot- 

 ing, the over and under ground organs are in constant 

 activity ; food is incessantly absorbed, which, however, 

 is but partially employed to increase the mass of leaves, 

 but not to form the stem. There is, therefore, every 

 reason to believe that the far larger portion of the or- 

 ganisable matter produced in the leaves during this 



