80 THE FATS AND LIPASES [ch. 



Of these, oleic acid (as glyccride) is the most widely disti-ibuted. 

 Yet other series are : 



The linolic C„H.„_A 



The linolenic CnH2^_602 



The clupanodonic Cnli^n-sOi 

 The ricinoleic C„H.,„_203 



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 nucifera) 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 usitatissimam 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 "/o- 



Palmaceae : Oil Palm {Elaeis guinensis) 62 "/o: Coconut Palm (Cucos 

 nucifera) G5 7o- 



Juglandaceae : Walnut (Juglans regia) 52 "/o- 



Betulaceae : Hazel {Corylas Avellana) o5°/o. 



Moraceae : Hemp {Cannabis saliva) 38 "/o- 



Papaveraceae : Opium Poppy (Fapaver somviferum) 47 "/o- 



Cruciferae : Garden Cress {Lepidium sativum) 25 "/„ : Black Mustard 

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

 {Brassica rapa var. oleifera) 33 "/o: Rape (Brassica napus) 42 "/o- 



Rosaceae: Almond {Prunus Amygdalus) 42 "/o: Peach {P. Persica) 

 35 Vo: Cherry (P. Cerasus) 35 "/o'- Plum (P. domestica) 27 "/o- 



Linaceae : Flax (Linum usitatissimum) 20-40 "/o- 



Euphorbiaceae : Castor-oil (Ricinus communis) 51 "/o- 



