ACCUMULATION OF NEW CHARACTERS. 



827 



In the case of many cultivated plants the original wild form is unknown. It is 

 possible that in a few cases it may have disappeared ; but it is more probable 

 that the varieties w^hich have arisen in cultivation have gradually acquired such a 

 number of new characters that their resemblance to the wild parent-form can no 

 longer be traced. This is probably the case with the cultivated Cucurbitacese, 

 gourds, bottle-gourds, melons, water-melons, &c., the hundreds of varieties of which 

 were traced back by Naudin to three primitive forms, Cuciirbita Pepo, maxima, and 

 moschata, neither of which how^ever is known in the wild state. These original forms 

 have been as it were evolved from the resemblances and differences of the number- 

 less varieties, and have only an ideal existence ; it is doubtful whether either of them 

 ever actually existed, or whether these ideal parent-forms do not merely correspond 

 to three principal varieties which arose from a single primitive form which possibly 

 still exists, or from the hybridisation of several. The characters of many of these 

 varieties are perfectly hereditary, and all the organs show the greatest degree of vari- 

 ation ; how great and various these differences are is seen from the fact that Naudin 

 has divided the group of forms which he included under the name Ciiciirbita Pepo 

 into seven sections, each of which again includes a number of subordinate varieties^ 

 The fruit of one variety exceeds that of another variety more than two thousand fold 

 in size ; the original form of the fruit is probably ovoid, but in some varieties it is 

 elongated into a cylinder, in others abbreviated into a flat plate ; the colour of the 

 rind varies almost infinitely in the different varieties ; in some it is hard, in others 

 soft; some have a sweet, others a bitter flesh ; the seeds vary in length from 5 or 7 

 to 25 mm. ; in some the tendrils are of enormous size, in others they are altogether 

 wanting ; in one variety they are transformed into branches which bear leaves, flowers, 

 and fruits. Even characters which are normally constant throughout entire natural 

 orders become extremely variable in the gourds; thus Naudin (Compt. rend. 1867, 

 vol. LXIV, p. 929) describes a Chinese variety o'i Cucurbiia maxima which has a per- 

 fectly free or superior ovary, whereas it is inferior elsewdiere in the Cucurbitaceae and 

 in the nearly allied orders I 



The varieties of melon {Cucumis Meld) Naudin divides into ten sections, which 

 differ also not only in their fruit, but also in their leaves and their entire habit or 

 mode of growth. Some melons are no larger than small plums, others weigh as 

 much as 66 lbs. ; one variety has a scarlet fruit ; another is only i inch in diameter 

 but 3 feet long, and is coiled in a serpentine manner in all directions, the other 

 organs being also greatly elongated. The fruits of one variety can scarcely be dis- 

 tinguished externally or internally from cucumbers ; one Algerian variety suddenly 

 splits up into sections when ripe (Darwin, I.e. vol. I, p. 357). 



The behaviour of the genus Zea is similar to that of Cucurbita. The cultivated 

 varieties of maize are probably descended from a single primitive wild form which has 

 been cultivated in America for a very long period ; but it seems doubtful whether 

 the native Brazilian species, the only one known in the wild state, with long glumes 



^ See Metzger, Landwirthschaftliche Pflanzenkunde, p. 692, and Darwin, /. c. vol. I, p. 358. 



^ Hooker states that a specimen oi Begonia frigida at Kew produced, in addition to male and 

 female flowers with inferior ovary, also hermaphrodite flowers with superior ovary. This variation 

 was the product of seeds from a normal flower. (Darwin /. c. p. 365.) 



