312 THE PHENOMENON OF 



the most considerable deviations from the normal character 

 of species occur, are not produced on the individual stock, 

 to whatever influences of nature and art this may be 

 exposed, but are connected with the reproduction in their 

 origin, since they grow up, as it were accidentally; from 

 seeds. Among these are many varieties very striking in 

 reference to the degree of division of the leaves, e.g. 

 simple-leaved forms of plants which, in the parent-form, 

 have ternate or pinnate leaves {Fragaria vesca mono- 

 phylla,^ Fraxinus excelsior simplicifolia),\ and vice versa, 

 divided-leaved modifications of plants, with normally un- 

 divided leaves or leaflets {Alnus c/htinosa laciniosa, Betula 

 alba laciniata v.dalecarlica),X Corylus Avellana laciniata, 

 Cytisus Laburnum quercifolius, Vitis vinifera laciniosa ;\ 

 also unarmed varieties of normally spinous plants [Bobinia 

 Pseudoacacia inermis) ; 1| varieties in reference to the colour 

 of the leaves {Fagus sylvatica sanguinea,^ Corylus tubulosa 



* Raised by Duchesne, in the year 1761, from seeds of the common 

 Fragaria vesca, and usually returning, when the seeds are sown, to the 

 parent-form with ternate leaves. Duchesne, ' Hist, des Praisiers,' p. 124 ; 

 Godron, ' De I'Espece et des Races,' p. 36. 



t Fr. simplicifolia, W., {heterophi/lla, Vahl.) In De Candolle's ' Pro- 

 dromus,' (viii, p. 276,) it is mentioned as a peculiar species, occurring in 

 England and Ireland, while Sprengel, (' Syst. Veget.,' i, 97,) places its 

 nativity in North America ! De Candolle, to establish the specific distinc- 

 tion, gives, in addition to the form of the leaf, certain characters derived 

 from the size and form of the fruit, which, however, I am compelled to regard 

 as an unimportant individuality of De Candolle's specimens, since the trees 

 of the simple-leaved ash, cultivated in the Botanic Garden of Garlsruhe, 

 agree exactly with the common ash, {F. excelsior,) in their fruit. Persoon, 

 in reference to the origin of this variety, says expressly, (' Syn.,' ii, 604,) 

 " e seminibus Fraxini elatioris vulgaris ortam vidi." Spenner found, on the 

 Sohieuberg, near Freiburg, a completely analogous variety of Ruhts Mmus, 

 with leaves resembling those of R. arcticus. 



X Both occur, probably only isolated, in Sweden and Lapland. In 

 gardens they are increased by cuttings, and when sown probably recur to the 

 entire-leaved parent forms. The other examples named are known only as 

 garden-plants. 



5 The parsley-vine, as it is called. See Babo and Metzger, ' Wein u. 

 Tafeltrauben,' p! 33, h. ii, 10. 



II A single specimen of this was obtained by Descemet from a sowing in 

 1803, and it is now generally diffused. Its seeds furnish the spiny parent- 

 form again. (See Clievreul, 'Considerations gen. sur les Variations,' &c. 

 'Ann. des Sc. nat.,' 3me s6r., vi, 157, 1846; Trans, iu 'Journ. Hort. 

 Society,' vol. vi, p. 51, 1851.) 



•([ The copper-beech universally diffused in gardens is derived from 



