STOCKS FOR CITRUS TREES. 203 



juice; those on the rough lemon .91 per cent acid and 

 7.24 per cent sugar determined as dextrose, a difference 

 of .19 per cent acid and 2.56 per cent sugar. Too much 

 weight must not be laid on these results, as many analyses 

 should be made to establish any difference which may 

 exist. 



This stock has a marked influence om the fruitfulness 

 of the Bahia navel orange in Florida. It is much more 

 prolific on rough lemon stock and with the exception of 

 C. trifoliata, it is the only stock which can be recom- 

 mended for the variety in that State. As a stock for pom- 

 elos and the oranges of the mandarin group, it is preferred 

 by some growers to all others. Rough lemon is resistant 

 against the attacks of mal-di-goma, or foot-rot, in this 

 respect ranking with the sour orange. 



TRIFOLIATE ORANGE (C. TRIFOLIATA). 



Perhaps the first mention of this species as a stock 

 for citrus trees is that made by Mr. Fortune, who in 1848 

 said, "The kumquat is propagated by grafting on a 

 prickly, wild species of citrus, which seems of a more 

 hardy nature than the kumquat itself." This remark un- 

 doubtedly referred to the trifoliate orange. The tree it- 

 self was described and illustrated by Kaempfer in his 

 Amoenitatum exoticarum in 1712. Undoubtedly it has 

 been used for ages by the Chinese and Japanese as a stock 

 for citrus trees, but it is only within recent years that trees 

 have been worked on this stock in America. Its use on 

 any extensive scale dates back only about eight or ten 

 years, but even yet its exact limitation of soil and cli- 

 mate have not been fully determined. 



Of all the stocks used for citrus trees, it is the hardi 

 est and it has, in some degree, the power in the colder 



