IN FOKEIGN COUNTRIES. 807 



that .there may be no difficulty in determining their localities after- 

 wards. Notes as to elevation (if above 2000 feet of the sea level), 

 dates, name of district, and any other information, should be attached 

 to the specimens to which they refer. A collector cannot be too care- 

 ful in regard to these matters. Ascertaining the temperature of the 

 trunks of evergreen and deciduous trees, and of the soil at their roots, 

 is a subject of importance. The temperature of the soil at various 

 depths during winter should be recorded ; also the temperature of the 

 air and water between the under surface of melting snow-beds and the 

 subjacent dormant vegetation, with the view of determining the causes 

 of the rapidity with which plants germinate and blossom after the 

 disappearance of snow from alpine situations.* 



• For fuller details, see instructions by Sir Wm. Hooker and Dr. Hooker, in Kew Miscel- 

 lany, vol. iz. pp. 214-219. 



