56 
JOUENAL OF THE ROYAL IIOKTICULTUIiAL SOCIETY. 
as has already been pointed out, ascend to considerable elevations. The 
total phanerogamic Hora of the Alps above 5,000 ft. is probably at least 
900 species. 
The following families are especially rich in alpine species : — 
One family, the GlobulariacefB (Selaginia^), is represented in Switzer- 
land entirely by alpine or sub-alpine species. A few genera, such as 
Androsace, Soldanella, and some others, are also almost entirely alpine. 
As a rule, however, genera which are rich in alpine species have also 
one or more lowland representatives. The following genera have the 
largest number of alpine species : — 
Anemone 
Hedum 
Campanula 
Eanunculus 
Sempervivum 
Gentiana 
Aconitum 
Baxifraga 
Pedicularis 
Arabis 
Valeriana 
Androsace 
Draba 
Erigeron 
Primula 
Viola 
Artemisia 
Salix 
Silene 
Achillea 
J uncus 
Arenaria 
Senecio 
Luzula 
Trifolium 
Cnicus 
Carex 
Oxytropis 
Crepis 
Poa 
Astragalus 
Hieracium 
Potentilla 
Phyteuma 
Many alpine species belonging to these genera are commonly culti- 
vated in our rock-gardens. The fact that many alpines wdll flourish in 
our plains is not a little surprising if we take into consideration the 
entire change in every detail of the environment which such plants must 
have to contend with. How is it that we are able to grow alpines 
at all in London ? From the point of view of the cultivator of alpines, 
this is perhaps the most important question arising from this subject, and 
it is only within a comparatively recent period that botanists have been in 
a position to offer an explanation of this phenomenon. Even now the 
explanation can hardly be regarded as complete. 
If we were to transplant a number of alpines from their mountain 
homes to one of our rockeries, we should find that all do not flourish 
equally. Some alpines refuse to grow at all in England, except perhaps 
under the most skilful cultivation. Others will flourish for a time, a few 
years perhaps, and then die ; while others, again, quickly adapting them- 
selves to their new surroundings, will survive. These latter are said to 
have the power of acclimatisation in a marked degree, or, as Pailey* puts 
it, possess the power of overcoming climate. This power of acclimatisation 
varies in degree in different plants. We have already seen instances of 
this in our study of the Swiss alpine flora. It has been pointed out that 
Gramine^e 
Cyperacene 
Compositse 
Caryophyllacefe 
CruciferfB 
Primulaceje 
Ranunculace;e 
Saxifrageae 
Leguminosje 
ScrophulariacejE 
Umbellifera^ 
Gentianacefe 
* Bailey, L. H., TJie Survival of the Unlike, p. 320. 
