Transactions of the Horticultural Society. 1 79 



country affords a proof that the neighbourhood of water ex- 

 posed to the air is not injurious to trees, provided the soil in 

 which they grow be two or three feet higher than the water. 

 It would appear, from Mr. Robertson's experience, and the 

 vigorous growth of fruit trees on the canal banks in Holland, as 

 noticed in Neill's very interesting Horticultural Tour (p. 260.), 

 that fruit trees so situated will thrive and bear abundantly, 

 with less bulk of soil for their roots, than under the ordinary 

 circumstances of soil without exposed water. Water, in con- 

 tact with air, becomes more or less impregnated by it, and 

 may, in that state, afford to plants a more abundant supply of 

 oxygen, the vital principle both of plants and animals. 



14. On Dahlias. By Mr. William Smith, Under-Gardener in the 

 Arboretum Department of the Garden of the Horticultural 

 Society at Chiswick. 



The greatest improvement in the culture of dahlias has been 

 the production of dwarfs. " For these desirable kinds of dahlias, 

 we are principally indebted to William Wells, Esq. His 

 gardener, Mr. Joseph Wells, possessing due knowledge of the 

 qualities he wished his productions to possess, has succeeded 

 in raising sorts which combine dwarfishness with early and 

 abundant flowering, and produce blossoms of the most beauti- 

 ful description. They begin flowering in June, when not 

 above a foot high, and continue to blossom in constant succes- 

 sion, till the autumn frosts divest them of their beauty ; they 

 seldom exceed three feet in height, and some are even more 

 dwarf" 



The varieties of the dahlia are as endless as those of the 

 garden ranunculus ; both produce abundance of seeds, and 

 of both it may be said that no two seedlings were ever found 

 alike. Mr. Smith remarks that " a few of the double 

 dahlias which were raised at an early period 5 still hold a 

 place in the estimation of gardeners, but, in general, those of 

 a few years' standing have yielded their places to a younger 

 progeny, which in their turn may be deprived of their station 

 by fresh productions. In the progress of improvement, it 

 may be hereafter a matter of curiosity to ascertain what was 

 considered a good dahlia at the present period ; this, without 

 a record such as this paper will furnish, would be impossible. 

 Thus we may indulge the hope that, in drawing up descriptions 

 of the best flowers of the present day, we are not only amusing 

 contemporary readers, but securing information to futurity." 



Description of a good Double Dahlia. — " The flower 

 should be fully double, always filling the centre ; the florets 



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