80 THE FATS AND LIPASES [CH. 



Of these, oleic acid (as glyceride) is the most widely distributed. 

 Yet other series are : 



The linolic C n H an _ 4 O a 



The linolenic C n H 2n _ 6 O 2 

 The clupanodonic C n H 2n _ 8 O. 2 

 The ricinoleic, C n H 2n _ 2 3 



The fat which occurs in an oil-containing seed is not composed of 

 the glyceride of one acid, but is a mixture of the glycerides of several, 

 or even a large number of different acids, often members from more 

 than one of the above series. Thus the fat of the fruit of the Coconut 

 (Cocos nuciferd) consists of a mixture of the glycerides of caproic, capry- 

 lic, capric, lauric, myristic, palmitic and oleic acids. Linseed oil from 

 the seeds of Linum usitatissimum again is a mixture of the glycerides 

 of palmitic, myristic, oleic, linolic, linolenic and isolinolenic acids. Simi- 

 lar mixtures are found in other fruits and seeds. 



Since glycerol is a trihydric alcohol, it would be possible for one or 

 more of the three hydroxyls to react with the acid to form mono-, di- or 

 tri-glycerides. All these cases occur and, sometimes, one hydroxyl is 

 replaced by one acid, and another hydroxyl by a different acid. 



When the distribution of fats among the flowering plants is con- 

 sidered, they are found to be more widely distributed than the botanist 

 is generally led to suppose. 



The following is a list of some of the plants especially rich in fats 

 as reserve material in the fruits or seeds. It represents only a selection 

 of the better known genera, since many other plants have fatty seeds. 

 An approximate percentage of oil present in the fruit or seed is given. 



Graminaceae : Maize (Zea Mays) 4 %. 



Palmaceae : Oil Palm (Elaeis guinensis) 62 / : Coconut Palm (Cocos 

 nucifera) 65 %. 



Juglandaceae : Walnut (Juglans regia) 52 / . 



Betulaceae : Hazel (Cory I us Avellana) 55 / . 



Moraceae : Hemp (Cannabis sativa) 33 %. 



Papaveraceae : Opium Poppy (Papaver somniferum) 47 %. 



Cruciferae : Garden Cress (Lepidium sativum) 25 % : Black Mustard 

 (Sinapis nigra) 20/ : White Mustard (Sinapis alba) 25/ : Colza 

 (Brassica rapa var. oleifera) 33/ : Rape (Brassica napus) 42/ . 



Rosaceae: Almond (Prunus Amygdalus) 42/ : Peach (P. Persica) 

 35%: Cherry (P. Cerasus) 35%: Plum (P. domestica) 27%. 



Linaceae : Flax (Linum usitatissimum) 20-40 %. 



Euphorbiaceae : Castor-oil (Ricinus communis) 51 %. 



