94 FIELD, FOREST AND FARM 



branches if the potato is placed in favorable condi- 

 tions. On old potatoes, late in the season, the buds 

 are seen to send forth sprouts which need only a lit- 

 tle sunshine to turn green and become stalks. Agri- 

 culture makes good use of this peculiarity : to propa- 

 gate the plant it is customary to put into the ground, 

 not the seeds, which would yield no harvest before 

 the lapse of several years, but the tubers, which pro- 

 duce abundantly the same year. Or else the potato 

 is cut into pieces and each piece, planted in the 

 ground, sends up a new plant on condition that it has 

 at least one eye ; if it has none it rots without pro- 

 ducing anything. 



"Furthermore, you can see on the eyes tiny little 

 scales, which are leaves modified to adapt them to an 

 underground life, leaves with the same right to the 

 name as the tough scales of an ordinary bud. Since 

 it has leaves and buds the potato is therefore a 

 branch. Should there remain any lingering doubts 

 on this subject, it might be added that by earthing 

 up the plant, that is to say by heaping soil around 

 the stalk, the young branches thus buried can be 

 converted into potato-bearers; and it might also be 

 added that in rainy and cloudy seasons it is not rare 

 to see some of the ordinary branches thicken and 

 swell up in the open air, and thus produce potatoes 

 more or less perfect. Accordingly the potato is to 

 be regarded as an underground branch swollen with 

 nourishment — in short, a tuber. 



' ' Many other plants produce similar branches that 

 grow under ground. In this number is the Jerusa- 



