Chap. X. TREES. 361 



Paul's nursery. 145 In the case of trees, all the recorded varieties, as far as 

 I can find out, have been suddenly produced by one single act of variation. 

 The length of time required to raise many generations, and the little value 

 set on the fanciful varieties, explains how it is that successive modifications 

 have not been accumulated by selection ; hence, also it follows that we do 

 not here meet with sub-varieties subordinate to varieties, and these again 

 subordinate to higher groups. On the Continent, however, where the 

 forests are more carefully attended to than in England, Alph. De Candolle 146 

 says that there is not a forester who does not search for seeds from that 

 variety which he esteems the most valuable. 



Our useful trees have seldom been exposed to any great change of con- 

 ditions ; they have not been richly manured, and the English kinds grow 

 under their proper climate. Yet in examining extensive beds of seedlings 

 in nursery-gardens considerable differences may be generally observed in 

 them ; and whilst touring in England I have been surprised at the amount 

 of difference in the appearance of the same species in our hedgerows and 

 woods. But as plants vary so much in a truly wild state, it would be 

 difficult for even a skilful botanist to pronounce whether, as I believe to 

 be the case, hedgerow trees vary more than those growing in a primeval 

 forest. Trees when planted by man in woods or hedges do not grow where 

 they would naturally be able to hold their place against a host of com- 

 petitors, and are therefore exposed to conditions not strictly natural : even 

 this slight change would probably suffice to cause seedlings raised from 

 such trees to be variable. Whether or not our half-wild English trees, as 

 a general rule, are more variable than trees growing in their native forests, 

 there can hardly be a doubt that they have yielded a greater number of 

 strongly-marked and singular variations of structure. 



In manner of growth, we have weeping or pendulous varieties of the 

 willow, ash, elm, oak, and yew, and other trees ; and this weeping habit is 

 sometimes inherited, though in a singularly capricious manner. In the 

 Lombardy poplar, and in certain fastigate or pyramidal varieties of thorns, 

 junipers, oaks, &c, we have an opposite kind of growth. The Hessian 

 oak, 147 which is famous from its fastigate habit and size, bears hardly any 

 resemblance in general appearance to a common oak ; " its acorns are not 

 sure to produce plants of the same habit ; some, however, turn out the 

 same as the parent-tree." Another fastigate oak is said to have been found 

 wild in the Pyrenees, and this is a surprising circumstance ; it generally 

 comes so true by seed, that De Candolle considered it as specifically dis- 

 tinct. 148 The fastigate Juniper (J. suecica) likewise transmits its character 

 by seed. 149 Dr. Falconer informs me that in the Botanic Gardens at 

 Calcutta the great heat causes apple-trees to become fastigate; and we 



145 ' Gardener's Chronicle,' 1866, p. i« Loudon's * Arboretum et Fruti- 

 1096. cetum,' vol. iii. p. 1731 



146 « Geograph. Bot.,' p. 1096. mb Ibid>> yol iv 24g9 

 W ' Gardener's Chron.,' 1842, p. 36. 



