360 



CUCURBIT ACEOUS PLANTS— TREES. 



Chap. x. 



of melons, in which the fruit is so like that of the cucumber, " both exter- 

 nally and internally, that it is hardly possible to distinguish the one from 

 the other except by the leaves." The varieties of the melon seem to be 

 endless, for Naudin after six years' study has not come to the end of them : 

 he divides them into ten sections, including numerous sub-varieties which 

 all intercross with perfect ease. 143 Of the forms considered by Naudin to 

 be varieties, botanists have made thirty distinct species ! ' ' and they had 

 not the slightest acquaintance with the multitude of new forms which have 

 appeared since their time." Nor is the creation of so many species at all 

 surprising when we consider how strictly their characters are transmitted 

 by seed, and how wonderfully they differ in appearance : ' ' Mira est quidem 

 foliorum et habitus diversitas, sed multo magis fructuum," says Naudin. 

 The fruit is the valuable part, and this, in accordance with the common 

 rule, is the most modified part. Some melons are only as large as small 

 plums, others weigh as much as sixty-six pounds. One variety has a scarlet 

 fruit ! Another is not more than an inch in diameter, but sometimes more 

 than a yard in length, " twisting about in all directions like a serpent." It 

 is a singular fact that in this latter variety many parts of the plant, namely, 

 the stems, the footstalks of the female flowers, the middle lobe of the leaves, 

 and especially the ovarium, as well as the mature fruit, all show a strong 

 tendency to become elongated. Several varieties of the melon are interest- 

 ing from assuming the characteristic features of distinct species and even 

 of distinct though allied genera: thus the serpent-melon has some re- 

 semblance to the fruit of Trichosanthes anguina ; we have seen that other 

 varieties closely resemble cucumbers ; some Egyptian varieties have their 

 seeds attached to a portion of the pulp, and this is characteristic of certain 

 wild forms. Lastly, a variety of melon from Algiers is remarkable from 

 announcing its maturity by " a spontaneous and almost sudden disloca- 

 tion," when deep cracks suddenly appear, and the fruit falls to pieces ; and 

 this occurs with the wild 0. mornordica. Finally, M. Naudin well remarks 

 that this "extraordinary production of races and varieties by a single 

 species, and their permanence when not interfered with by crossing, are 

 phenomena well calculated to cause reflection." 



Useful and Oenamental Teees. 



Teees deserve a passing notice on account of the numerous varieties 

 which they present, differing in their precocity, in their manner of growth, 

 foliage, and bark. Thus of the common ash (Fraxmus excelsior) the cata- 

 logue of Messrs. Lawson of Edinburgh includes twenty-one varieties, some 

 of which differ much in their bark; there is a yellow, a streaked reddish- 

 white, a purple, a wart-barked and a fungous-barked variety. 144 Of hollies 

 no less than eighty-four varieties are grown alongside each other in Mr. 



Memoir on Cucumis in ' Annal. des Sc. 

 Nat.,' 4th series, Bot. torn. xi. 1859 

 p. 5. 

 143 See also Sageret's ' Memoire,' 



p. 7. 



144 Loudon's 'Arboretum et Fruti- 

 cetum,' vol. ii. p. 1217. 



