Carthamus tinctorius (Safflower)

A thistle-like herb with yellow flower heads that originates from the Middle East. It has been cultivated since ancient times and is not known from nature. The original main reason for its cultivation was that the dried flowers yielded a valuable red dye containing the pigment carthamine, which was used to colour cloth. However, synthetic aniline dyes have taken over. Nowadays Safflower is cultivated mainly to produce edible oil from the seed-like fruits. This oil contains the highest levels of linoleic acid (a polyunsaturated oil) of any seed oil and is used in margarines, salad oils and cooking oil.

Helianthus annuus (Sunflower)

yielding: sunflower oil, yellow margarine

Sunflowers originate from North America and are now grown extensively for their seeds which produce vegetable oil that is used in cooking, salad oils and margarines. The residue after oil extraction provides a high protein food source for livestock. 

Brassica napus (Rape, Oilseed rape, Canola)

Brassica napus is native to Eurasia and has a number of varieties that are cultivated widely round the world for the production of vegetable oil. Canola is a variety of Brassica napus developed in Canada that contains low concentrations of erucic acid and glucosinolates and the name is derived from the words  CAnadian Oilseed Low_Acid. It is grown mainly for the production of cooking oil and Canola margarine, and has been cultivated in South Africa since 1994.

Olea europaea (Olive)

yielding: olive oil