CH. x] THE PLANT BASES 155 



The betaines are amino-acids in which the nitrogen atom is com- 

 pletely methylated, and, with one or two exceptions, this grouping does 

 not occur in the true alkaloids. The betaines have only feebly basic 

 properties. 



The alkaloids, in contrast to the simpler natural bases, are rather 

 restricted in their distribution, many being limited to a few closely 

 related species or even to one species. 



The purine bases are a small group of substances intimately related 

 to each other and to uric acid. 



AMINES. 



Methylamine, CH 3 . NH 2 , occurs in the Annual and Perennial Dog's 

 Mercury (Mercurialis annua and M. perennis) and in the root of the 

 Sweet Flag (Acorus Calamus). 



Trimethylamine, (CH 3 ) 3 . N, occurs in leaves of the Stinking Goose- 

 foot (Chenopodium Vulvaria), in flowers of ,the Hawthorn (Crataegus 

 Oxyacantha) and Mountain Ash (Pyrus Aucuparia), and in seeds of 

 Mercurialis annua. 



Ptitrescine, NH 2 (CH 2 ) 4 .NH 2 , occurs in the Thorn Apple (Datura) 

 and tetramethylputrescine in a species of Henbane (Hyoscyamus 

 muticus). 



Hordenine occurs in germinating Barley grains. It is represented 

 as: 



o'CH 2 -N(CH 3 ) 2 



Pyrrolidine is said to occur in small quantities in leaves of the 

 Carrot (Daucus Carota) and Tobacco (Nicotiana) leaves. It is repre- 

 sented as : 



CH 2 - CH 2 



I ' I 

 CH 2 CM* 



Other amines occur among the lower plants (Fungi). 

 Choline is sometimes classified with the betaines. It is however 

 intimately connected with the phosphatides (compounds of the fatty 

 acids with phosphoric acid and nitrogen) which is not the case with the 

 betaines. It may be represented as : 



OH 

 (CH 3 ) 3 : N< 



X CH 2 CH. 2 OH 



