MONOGRAPHY OF THE GENUS CAMELLIA. 33 



its leaves, and often, it is not in the power of the horticulturist, to prevent 

 it from perishing. Such is the fate of the forced Camellia, which are des- 

 tined to decorate our saloons in winter, and furnish the tribute of their bril- 

 liant flowers, during the season of magnificent entertainments. 



An equality of temperature is therefore, essential, for the preservation 

 of the buds. A too sudden change, whether it arise from the momentary in- 

 troduction of cold air into the green-house, at the time when the heat is up 

 to from 54 to 60 degrees, or from a too great elevation of the temperature, 

 to from 60 to 65, too suddenly introduced, when the thermometer, indicates 

 but 32 degrees} both of these sudden and violent transitions produce the 

 same results, — the fall of the buds : the reason appears to us evident. 



When the buds are near expanding into blossom, a mild and continued 

 heat causes them to advance rapidly, the vegetation of the Camellia, being 

 then confined to only this part of the plant. If then, to an excessive eleva- 

 tion of the atmosphere, there succeeds a considerable reduction of the heat, 

 the sap, operated upon by this sudden change, is checked; the buds no longer 

 receiving nourishment, as abundantly as before, they become dry and fall. 



A physiologist cannot fail to notice, with deep interest, how powerfully 

 the heat and cold, instantaneously acts, upon the buds, when they have 

 reached a certain degree of development. The slightest difference of tem- 

 perature affects them considerably. 



The necessity then, cannot be too earnestly insisted upon, of keeping the 

 heat of the green-house, at all times very near the same degree of elevation. 

 In the spring, this regularity is less necessary, because there is nothing to be 

 feared from such sudden transitions, and the solar heat is daily increasing; 

 but, in winter, the atmospheric variations, being so frequent and instan- 

 taneous, and the life of the plants being confided to artificial means, it can 

 be easily conceived, that much greater vigilance is. necessary to regulate, 

 according to the circumstances, the temperature which they require. 



To act in conformity to these established principles, it is necessary to 

 have two thermometers in the green-house, one being placed on the rear and 

 the other on the front wall, and to examine them attentively several times 

 every day. When the temperature falls as low as 38, the doors and sashes 

 should be immediately closed; and if, notwithstanding this precaution, the 



