TEMPERATE FLORAS 39 



alpine flora really partakes of that poverty wliicli appertains 

 to liigii latitudes. It is the novelty and beauty of alpine 

 plants that are so attractive to the botanist and so entrancing 

 to the lover of nature, that give an impression of abundance 

 which is to some extent deceptive, and this is increased by 

 the fact that Avhole groups of plants which are more or less 

 rare in the lowlands are plentiful at higher altitudes. Two 

 other circumstances add to this impression of abundance — 

 alpine flowers are mostly very dwarf, and being all at the 

 same level, attract the eye more than when distributed over 

 various heights from that of the creeping herb to the summit 

 of lofty trees ; and, in addition to this, the shortness of the 

 season of growth leads to a much larger proportion of the 

 species flowering together than on the lowlands at the same 

 latitude. 



Extra-European Temperate Floras 



The number of floras which are available for comparison 

 with those of Europe are few in number and yqxj widely 

 scattered ; but they serve to illustrate the fact already dwelt 

 upon, that the dift'erences of species-j^opulation in fairly com- 

 parable areas approach to a general uniformity all over the 

 world. 



Boulder County is probably one of the most favourably 

 situated areas in the United States. It is onlv a little west 

 of the centre of the country; it comprises warm valleys and 

 one of the highest of the Rocky Mountain summits. Long's 

 Peak, and being in the latitude of southern Italy and Greece, 

 has abundant sunshine and a warm summer temperature. 

 It thus agrees in physical conditions with some of the alpine 

 cantons of Switzerland, and the number of its flowering 

 plants is almost identical with the average of Zurich, St. Gall, 

 Schwyz, etc., which have almost the same mean area. 



Washington, D.C., with an undulating surface just above 

 the sea-level, and a fair amount of forest and river-swamp, 

 agrees very well with the mean of Strasburg and Schaff- 



