260 ORIGIN OF CULTIVATED PLANTS. 



mens, attriVjutes only G. turhinatus to trigonus. The 

 specific diHcrence between G. Melo and G. trigonus is 

 unfortunately oLscure, from the characters given by 

 these three authors The principal difierence is tliat 

 G. Melo is an annual, the Gth3r perennial, but this dura- 

 tion does not appear to be very constant. Mr. Clarke 

 says himself that G. Melo is perhaps derived by cultiva- 

 tion from G. trigonus ; that is to say, according to him, 

 from the forms which Naudin attributes to G. Melo. 



The experiments made during three consecutive years 

 by Naudin^ upon the products of Gw,umis trigonus, 

 fertilized by G. Melo, seem in favour of the opinion which 

 admits a specific diversity ; for if fertilization took place 

 the products were of different forms, and often reverted 

 to one or other of the original parents. 



2. The African forms. Naudin had no specimens in 

 sufiiciently good condition, or of which the wnld state 

 was sufiiciently certain to assert positively the habitation 

 of the species in Africa. He admits it with hesitation. 

 He includes in the species cultivated forms, or other wild 

 ones, of which he had not seen the fruit. Sir Joseph 

 Hooker ^ subsequently obtained specimens which prove 

 more. I am not speaking of those from the Nile Valley,^ 

 which are probably cultivated, but of plants gathered by 

 Barter in Guinea in the sands on the banks of the Nig-er. 

 Thonning ^ had previously found, in sandy soil in Guinea, 

 a Cucumis to which he had given the name arenanus ; 

 and Cogniaux,^ after having seen a specimen brought 

 home by this traveller, had classed it with G. Melo, as 

 Sir J. Hooker thought. The negroes eat the fruit of the 

 plant found by Barter. The smell is that of a fresh green 

 melon. In Thonning's plant the fi'uit is ovoid, the size 

 of a plum. Thus in Africa as in India the species bears 

 small fruit in a wild state, as we might expect. The 

 Dudaini among cultivated varieties is allied to it. 



' Nandin, Ann. 8c. Nat., 4th series, vol. xviii. p. 171, 



* Hooker, in Oliver, Fl. of Trop. Afr., ii. p. 5-46. 



* Schweinfurth and Ascherson, Aufzahbtng, p. 267. 



* Schumacher and Thonnincj, Guineiske Planten., p. 425. 

 ' Cogniaux, in de Candolle, Monogr. Fhandr., p. 483. 



