110 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



siderable number found in nature only on chalk, and perhaps a 

 smaller number only found off it. The flora of the chalk is 

 exceptionally rich. 



Of Alpine culture generally I am not treating to-day ; but 

 I think it well to make a remark or two on this subject. The 

 great difference between the two typical soils which I have named 

 seems to be a mechanical one. The chalk is of a sticky nature, 

 and holds water for the plant winter and summer. Those plants 

 which by nature or habit exact such constant moisture, and do 

 not resent a clinging embrace from the soil, are the chalk-lovers. 

 I could instance a host of plants. Gentiana acaulis and verna, 

 Prim i da Auricula, Clusiana, and many other Primulas are rarely 

 found off the chalk in nature. So Dryas octopetala, Saxifraga 

 ccesia and squamosa, and a host of others which I could name. 

 It is singular to note how in the Dolomite range of mountains— 

 which is generally calcareous, but in which are strangely inter- 

 mingled mountains of syenite (a non-calcareous formation) — you 

 pass from one flora to another rapidly and often, and can tell the 

 soil you are traversing by the plants you see. Again, in the 

 Engadine, where the range is nearly wholly granitic, but where 

 there is a patch or two of chalk upcropping (chiefly on the 

 Albula Pass), it is only on these few patches that we can find 

 in the whole district such chalk-lovers as Dryas, the great Bell 

 Gentian, and Androsace chamcejasme. The place of Gentiana 

 acaulis is taken off the chalk by the similar and equally fine Bell 

 Gentian, Gentiana excisa — a hint, by the way, for those who find 

 they cannot grow the first-named species. I may here observe 

 that while in nature many plants are only found on chalk, it does 

 not follow that in cultivation they cannot be grown without it ; 

 and this for the very simple reason that art, assisted by our 

 humid climate, can readily supply otherwise the function of chalk 

 in maintaining a constant supply of moisture. In fact, I know 

 of no single chalk-loving plant which may not be grown, and well 

 grown, without it. On the other hand it seems, according to my 

 experience, to be the fact, and a fact easy to understand if what 

 I have just been writing be correct, that many plants found in 

 nature only off chalk cannot be successfully grown on it. I 

 incline to think that some of these " lime-haters," as they are 

 called, may find something impossible and poisonous to them in 

 its chemical constituents, so immediate are the effects. But, for 



