72 THE BOOK OF RARER VEGETABLES 
tuber being much sweeter and more floury, like Potatoes. 
The tubers command a much better price than the Potato, 
and at La Pax are largely cultivated •, the soil being most 
fertile, they grow freely. At Lima the leaves and tops of 
the plant are used as a salad, and even in this country I 
have seen it used in the same way as Spinach or Sorrel ; 
indeed it somewhat resembles the last named plant, as it 
contains a considerable quantity of oxalic acid. The 
young stems of this plant, also others of the species. 
TUBERS OF OKA-PLANT, OXALIS CRENATA 
(.One-third natural size) 
have been used in tarts ; but I should add, used thus the 
tarts would need a lot of sweetening or flavouring. The 
culture is peculiar *, the aim is to get as many tubers as 
possible from the stems. The soil must be light, rich, 
and warm, and the tuber is propagated like the Potato, 
leaving an eye to each tuber. Cuttings also take root 
freely if placed in a warm bed in March or April and 
planted out in May and June in rows 3 feet apart and 2 
feet between the plants. The shoots are best earthed 
up as growth is made, and this is continued several times 
till the early autumn — September — when the tubers begin 
to form. They will be ready for use in November and 
may be kept good for months if taken up and stored in 
sand in a cool place, kept quite dry, as damp or frost soon 
decays the tubers. The plant does not thrive in wet or 
