ACCUMULATION OF NEW CHARACTERS. 925 



have been traced back by Naudin to three primitive forms, Cucurhila Pepo, maxima, 

 and moschaia, neither of which however is known in the wild state. These original 

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

 numberless 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 variation ; how great and various these differences are is seen from the 

 fact that Naudin has divided the group of forms which he includes under the name 

 Cticurbita 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 fiat 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 of 

 Cucurhita maxima which has a perfectly free or superior ovary, whereas it is inferior 

 elsewhere in the Cucurbitaceae and in the nearly allied orders^. The varieties of 

 Melon {Cucumis Melo) 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 dd 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 distinguished 

 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 Cucurhita. 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 

 enveloping the grains, is the primitive form ; if it is not, then no plant is now known 

 which can be considered as the ancestral form of our numerous and extremely diverse 

 varieties of Maize. In this case also continued cultivation has increased the amount 

 of difference between the different varieties, as well as to a prodigious extent that 

 between them and the primitive form ; and the separate varieties are distinguished 

 from one another by a number of different characters. Some are only \\ feet high, 

 others as much as 15 to 18 feet; the grains stand on the rachis in rows varying from 



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



"^ Hooker states that a specimen of Begonia fri%ida 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.) 



