154 FREAKS OF PLANT LIFE. 



one of the seed-leaves moved upwards the opposite 

 one moved downwards. Although the up and down 

 movement was the most common, this was some- 

 times accompanied by lateral and zigzag oscillations. 

 In a great many cases the seed-leaves sink a little in 

 the forenoon and rise a little in the afternoon, so that 

 they stand rather more highly inclined during the 

 night than at mid-day, when they would be nearly 

 horizontal. The position of the seed-leaves by night 

 and by day was observed by Mr. Darwin in the 

 seedlings of plants in 153 genera. Of these there 

 were twenty-six in which the cotyledons stood 

 vertically at night, or at least sixty degrees above or 

 below the horizon. There were thirty-eight in which 

 the cotyledons (seed-leaves) which at noon were 

 horizontal were at night more than twenty and less 

 than sixty degrees above the horizon. In the 

 remaining eighty-nine the cotyledons did not 

 change their position at night so much as twenty 

 degrees. 



Proceeding with its growth, the plumule, or minia- 

 ture bud of the future stem and true leaves, rises 

 between the cotyledons, or seed-leaves, and as it 

 grows it nutates or rotates as the radicle and the 

 seed-leaves had done. 



Before quitting the seedling and its radicle some 

 mention must be made of a subject which occupies 

 an entire chapter of the work to which we have 



