170 PLANT BASES [ch. 



The betaines are ainino-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, CHg * NHg, occurs in the Annual and Perennial Dogs- 

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

 Flag {Acorus Calamus). 



Trimethylamine, (6113)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. 



Putrescine, NH2(CH2)4*NH2, 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 : 



H0<<; 3>CH2'CH2' N(CH3)2 



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

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

 sented as: 



CH2 CH2 



I I 



CH2 CH2 

 \nh/ 



Other amines occur among the lower plants (Fungi). 



Choline is sometimes classified with the betaines. It is however 

 intimately connected with lecithin (see p. 98) which is not the case with 

 the betaines. It may be represented as: 



.OH 

 (CH3)3: N<( 



XHo-CHoOH 



