I-J'CALYPTUS. 21 



a dry still atmosphere the rapid radiation causes frosts severe 

 enough to seriously injure and even kill young citrus trees. 

 The shortness of the young trees is one element of their 

 danger. The nearer the ground the greater the danger. 

 One writer says that the climatic range of the orange tree 

 is that of the blue gum and where one will grow so will 

 the other. In contradiction to this, reports to me from Ari- 

 zona mention citrus trees as successful and Eucalyptus a 

 failure. In this, case however it is said to be the prolonged 

 dry heat that unfavorably affects the Eucalyptus (Eucalyp- 

 tus globulus.) On the other hand the blue gum thrives 

 remarkably in the damp cool climate of the California coast 

 where the orange is a sad failure. About the Southern 

 confines of Los Angeles city where the blue gum is in 

 superb health and has a great development the orange tree 

 also thrives but gives an inferior fruit with excess of 

 acidity. 



I think that the orange and blue gum will resist about 

 the same degree of frost. 



It should not be forgotten that water is an equalizer of 

 temperature and helps frost resistance. Therefore if a frost 

 threatens, a full flooding irrigation will diminish the 

 danger. 



In a Washington, D. C., nursery there is a Eucalyptus, 

 species unknown, that for a number of years has been 

 frozen every winter, but which sprouts anew each spring. 

 In Paris the blue gum is sometimes used for ornament in 

 the parks. The way this is done is to plant the seed in 

 the open, transplant it to hot-house for winter, and set out 

 the second summer, leaving it to its fate in the succeeding 

 winter. 



In Australia the numerous species of Eucalyptus have 



