J50 © N THE NATURALIZATION OF PLANTS. 



mofily killed by the cold of the enfuing winter, while many 

 of the fame fpecies efcaped uninjured : and the fame may be 

 always obferved after every fevere winter *. 

 Sun/nine and Few deciduous fhrubs agree with (hade ; their natural place 



is the funny ontfkirts of the foreft; and when otherwife fituated, 

 long and flender branches, with large thin leaves, fhew their 

 unhealthy flate. From thefe the climbing plants are eafily 

 diftinguilhed by their tendency to contortion, or (hooting forth 

 roots or tendrils. To the deciduous climbers a flight (hade is 

 not hurtful, as it is only there they can find the neceflary fup- 

 port ; but in the deep recefles of the foreft, the evergreen 

 climbers will fpread around their tangling branches, and thrive 

 with wild luxuriance, 



Where fcarce a funbeam wanders through the gloom. 



Thomson's Seasons. 



never appearing, if the foil is fufficiently moift in fummer, to 

 be hurt by the thicken 1 (hade of deciduous trees, 

 fhade defends The (hade is alfo the natural fituation for young plants. By 

 plants from froft. the p arenta i ft ia d e they are proteded from the drought of fum- 

 mer, and the cold of winter. The more a plant is (haded in 

 winter, and the nearer it is to any large body, the lefs danger 

 it will be in of fuffering from froft. For when a plant or water 

 is fo fituated as to be overtopped by trees, a great part of the 

 hoar or frofty particles, which would fall on it, is intercepted. 

 Under trees we may often obferve water unfrozen, and plants 

 unhurt by the feverity of cold, and many retaining their leaves ; 

 when water at a fmall diftance is frozen, and plants of the fame 

 fpecies, but unfliaded, lofe their leaves and furTer confiderably. 

 As large bodies are not eafily cooled, the cold is in Come de- 

 gree mitigated by the items of large trees. That this is the 

 cafe maY be perceived, the twigs and fmaller branches being 

 covered with hoarfroft, when the trunk and larger branches 

 remain uncovered. 



* The following experiments may throw fome light upon the caufe 

 of plants remaining unfrozen, when the furrounding water is frozen. 

 Water enclofed in fcaled glafs globules remains unfrozen, till the 

 thermometer defcends to twenty-four ; unfealed ones freeze and 

 burft immediately on being cooled down to freezing water. Oil 

 enckild in the fame kind of globules continued unexpanded, and 

 confequently the globules unbroken, when placed in a mixture of 

 foow and fal ammoniac, and cooled below o, 



Dr, 



