422 ORIGm OF CULTIVATED PLANTS. 



three names for the sesame in these islands, very different 

 one from the other, and from the Sanskrit word, which 

 supports the theory of a more ancient existence in the 

 archipelago than on the continent. 



In conclusion, from the fact that the sesame is wild in 

 Java, and from historical and philological arguments, 

 the plant seems to have had its origin in the Sunda Isles. 

 It was introduced into India and the Euphrates valley 

 two or three thousand years ago, and into Egypt at a less 

 remote epoch, from 1000 to 500 B.C. It was transported 

 from the Guinea coast to Brazil by the Portuguese,^ but 

 it is unknown how long it has been cultivated in the rest 

 of Africa. 



Castor-oil Plant — Ricinus comominis, Linn^us. 



The most modern works and those in highest repute 

 consider the south of Asia to be the original home of this 

 Eui^horhiacea ; sometimes they indicate certain varieties 

 in Africa or America without distinsfuishinof the wild 

 from the cultivated plant. I have reason to believe that 

 the true origin is to be found in tropical Africa, in 

 accordance with the opinion of Ball.^ 



The difficulties with which the question is attended 

 arise from the antiquity of cultivation in different 

 countries, from the facility with which the plant sows 

 itself and becomes naturalized on rubbish-heaps and in 

 waste ground, lastly from the diversity of its forms, which 

 have often been described as species. This latter point 

 need not detain us, for Dr. J. MUller's careful monograph ^ 

 proves the existence of sixteen varieties, scarcely heredi- 

 tary, which pass one into the other by many transitions, 

 and constitute, therefore, but one species. 



The number of vaiieties is the sign of a very ancient 

 cultivation. They differ more or less as to capsules, 

 seeds, inflorescence, etc. Moreover, they are small trees 

 in hot countries, but they do not endure frost, and 

 become annuals north of the Alps and in similar regions. 

 They are in such cases planted in gardens for ornament, 



* Piso, Brazil., edit. 1658, p. 211. 



' Ball, Florae Maroccana Spicilegium, p. 664. 



' MUlJer, Argov., ia D.C., Prodromus, vol. xv. part 2, p. 1017. 



