The crudest method of rendering oils from seeds, still practised in Central Africa, in Indo-China and on some of the South Sea Islands, consists in heaping up oleaginous fruits and allowing them to melt by the heat of the sun, when the exuding oil runs off and is collected.
Large numbers of oleaginous plants are cultivated, such as sunflower.
The Rhine valley is in great part fertile, yielding good crops of potatoes, cereals (including maize), sugar beet, hops, tobacco, flax, hemp and products of oleaginous plants.
In the case of oleaginous seeds of low value (cotton-seed, linseed) it is of importance to express in one operation the largest possible quantity of oil.
Besides these, certain oleaginous plants, the suf, nuc and selite (there are no European equivalents for the native names), and the ground-nut are largely grown.
It has a very important market for cereals and oleaginous grains.
Their chief physical distinction from the fatty oils is that they are as a rule not oleaginous to the touch and leave no permanent grease spot.
In consequence of these more favourable conditions there is greater variety in the cropping; a good deal of wheat is grown, as well as beetroot for sugar, fibre plants and oleaginous plants, fruit, and even (W.