262 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION 



Orange trees, of course, proved themselves much hardier than 

 lemon trees. It was common to see lemon trees entirely defoliated, and 

 among them orange trees which had lost few or none of their leaves. 

 There were other places where the lemon trees were partly defoliated 

 and had split bark in the limbs, while the orange trees showed no 

 damage except in the fruit, and even here the damage was so limited 

 that the grower received good returns for his crop. 



In most places there seemed little difference in hardiness between 

 Washington navel trees and Valencias, this being especially true of the 

 bearing trees. 



In one locality, where there was not much damage to the bearing 

 orange trees, a careful comparison was made between the condition 

 of 250 young Valencias and the same number of navels. These trees 

 were all of the same age, two years and a half old at the time of the 

 freeze, and offered an opportunity for a perfectly fair comparison. 

 Fourteen per cent of the navels and 3 per cent of the Valencias had 

 the limbs killed; 64 per cent of the navels and 93 per cent of the 

 Valencias were largely defoliated without having the limbs killed; 

 22 per cent of the navels and 4 per cent of the Valencias were only 

 partially defoliated. In this case the navels were not less hardy than 

 the Valencias, but the amount of variation was greater in the navels. 

 More navels than Valencias were badly frozen, but there were also 

 more navels than Valencias among the trees which were only slightly 

 injured. 



The conflicting degrees of injury exhibited by these varieties in 

 different places indicate that they are naturally of about the same 

 degree of hardiness and that the differences observed in different 

 places were due to the varying condition of the trees at the time of 

 the freeze. 



There was a marked difference in the hardiness of the two principal 

 varieties of lemons, the Lisbons showing themselves decidedly more 

 resistant than the Eurekas. Temperatures low enough to cause Eureka 

 trees to drop three-fourths of their leaves were withstood by Lisbons 

 with practically no foliage damage and with some uninjured fruit. 

 Villafranca lemons proved somewhat hardier than Eurekas, but not 

 so hardy as Lisbons. In one nursery two-year-old Eureka and Villa- 

 franca trees on sweet stock were found side by side. The former trees 

 were frozen nearly to the buds, whereas only the upper half of the 

 Villafranca tops were killed. 



The grapefruit trees proved more hardy than lemon trees. The 

 fruit of the pomelo is never so easily frozen as the orange fruit, but 



