86 CULTIVATION. 



occurrence of very severe frost, heavy snow, or 

 violent rain. Slight frost or rain does no injury; 

 indeed there is more fear of over-covering and 

 preventing a full share of air and light than of 

 over-exposing the bed to the weather. 



If a bulb be frozen through, it and the flovver 

 will be killed, though the offsets may escape ; and, 

 if the exterior coats only be frozen, a diminished 

 stem and flower will afterwards be produced ; but 

 few or no leaves. This, it may be observed, is a 

 circumstance frequently witnessed in vegetation, 

 and particularly bulbs. If the exterior of a bulb 

 be chilled by cold, or over-dried by warm air, its 

 central and more vital part, being free from in- 

 jury, pushes forth before the leaves, and seems to 

 engross the whole vigour of the system. So, we 

 sometimes see, under the influence of the mid- 

 day sun, the flowers of a plant remain erect and 

 rigid, while its leaves are flaccid and drooping ; 

 because the flowers depend on the central vessels, 

 which are less exposed to desiccation than the ex- 

 terior. Branches of evergreen trees, as the holly 

 for instance, when denuded of every leaf, and 



