APPENDIX. 22* 



fectly. By the 16th of August they nad produced ripe and perfect 

 seeds ; the stalks and roots were, therefore, removed from the soil, and 

 treated as above. 



POLYGONUM FAGOPYRUM. 

 a. — In Pure Sand. 

 The buck-wheat, on the 8th of May, seemed to flourish the best of all 

 the plants grown on pure sand. By the end of June, it had reached a 

 height of 1 \ foot, and branched out. considerably. On the 28th of June, 

 it began to blossom, and continued to blossom till September, without 

 producing seeds. It would certainly have continued to blossom still 

 longer, had we not removed it from the soil on the 4th of September, as 

 it lost too many leaves : it was treated as before. 



B. — In Artificial Soil. 

 The buck-wheat grew very quickly in this soil, and reached a height 

 of 2i feet. It branched out so strongly, that it was necessary to support 

 it with a stick; it began to blossom on the 15th of June, and produced 

 perfect seeds, the greater number of which were ripe on the 12th of 

 August. On the 4th of September, it was taken from the soil along 

 with the roots, and treated as before, on account of losing too many 

 leaves from below ; although it was partly still in blossom, and with 

 unripe fruit. 



NICOTIANA TABACUM. 

 A. — In Pure Sand. 

 The tobacco-plant sown on the 10th of May did not appear till the 2d 

 of June, although it then grew in the normal manner ; when the plants 

 had obtained their second pair of leaves I removed the superfluous 

 plants, leaving only the five strongest specimens. These continued to 

 grow very slowly till the occurrence of frost in October, and obtained 

 only a height of five inches, without forming a stem. They were 

 removed along with their roots from the sand on the 21st October, and 

 treated as the above. 



B. — In Artificial Soil. 

 The tobacco sown on the 10th of May came up on the 22d of the 

 same month, and grew luxuriantly. When the plants obtained the 

 second pair of leaves, I withdrew the superfluous plants, and allowed 

 only the three strongest to remain. These obtained stems of above 

 three feet in height, with many leaves ; on the 25th of July they began 

 to blossom ; on the 10th of August, they put forth seeds ; and, on tht 



