16 Colour and other Characters in the Potato 



fixed, viz. the point from which the tubers grow out from the stolon, 

 and the most distal point from that, which in 19 out of 20 cases coin- 

 cides with the central of the crown of eyes at the distal end. It is 

 from this eye that the earliest and strongest shoot grows out. The 

 line between these two points is the long axis, the breadth and depth 

 are respectively the greatest measurements in each direction measured 

 at right angles to the long axis and to each other. Adopting the 

 conventional terms for potato shapes, the names long, kidney, pebble, 

 and round appear to have the following meanings : — 



A long potato is one in which the long axis is between \^ and 2| 

 times the greatest breadth, and the depth is equal to the breadth. 

 The ends are either blunt, as in the " Congo," giving the tuber a 

 cylindrical appearance, or they are pointed as in B, Plate XXIV. 



A kidney potato is one in which the length is usually between 

 1^ times and twice the breadth, and the depth is considerably less than 

 the breadth, giving the tubers a flattened appearance which is charac- 

 teristic. The measurements of three specimens, unselected, of well- 

 known " kidneys " are : — 



The Lapstone Potato is a bluntly elliptical or oval potato which is 

 much broader than it is deep. 



The Pebble Shape. This term includes a vast number of rather 

 irregularly shaped tubers — tubers for the most part obtusely elliptical 

 and almost as broad as they are long. 



