26 THE POTATO CHOP. 



Red Yam. Stem erect, spreading, and about 2 feet 

 high; tuber large and oblong; colour bright reddish; 

 waxy, indifferent flavour, but very healthy. An esteemed 

 variety for cattle feeding, the cultivation of which is 

 rapidly extending in the districts where it has been tried. 



The leading characteristics of the foregoing varieties 

 thus briefly given, were those noted by Mr, Lawson in his 

 experimental trials of the different varieties of the potato. 

 The experiments were all carried on in the same soil, a 

 medium loam of medium fertility, and thus well suited 

 for testing the relative values of the different sorts planted. 

 At the same time, we must recollect that one of the great 

 benefits derivable from varieties is the increased facili- 

 ties given for cultivation in a variety of soils ; therefore, 

 although the class of soil in question was perhaps the 

 best that could have been chosen for the experiment, it is 

 more than probable that very many of the varieties would 

 have changed their characters considerably had they been 

 grown in soils perfectly congenial with their habits of 

 growth. 



Before proceeding with the agricultural treatment of 

 the potato crop, it will be well to bear in mind that, 

 although it is usually looked upon by us as a root crop, 

 botanists have clearly shown us that the potato tuber is 

 not a root, but merely an enlargement of the underground 

 stem, due principally to cultivation, and caused by an ab- 

 normal increase of the cellular tissues, in which are depo- 

 sited the starch globules, which exist in such large pro- 

 portion in the tubers. If a seed of the potato be sown, it 

 germinates and sends forth true roots like those of any 

 other plant ; these have not the power to enlarge into the 

 form of a tuber their duty is to ramify through the soil 

 and search for food. The potato, like other plants, con- 

 sists of three parts the cellular and vascular tissues, and 

 the outer covering or skin. In its natural state, the ten- 



