INTRODUCTION. 



WHAT is the difference between an orange and a 

 lemon ? Various examples occur, which do not agree, 

 either with the popular definition of oranges and 

 lemons, or with that given by botanists. For instance 

 the k/ratta citrus of India has an orange leaf, an 

 orange exterior, an orange pulp, yet its fruit is 

 prominently mammillate, and its flower is tinged purple. 

 Again, the acidless citrus, the* mitha-nimboo, has a 

 lemon-yellow exterior, a white pulp, and it is mammil- 

 late ; its leaves are like those of a lemon, yet its flowers 

 are pure white. The jkamblri proper has orange-like 

 leaves, the flowers are slightly tinged with purple, the 

 pulp, varies from white to pale yellow, or orange, and 

 the fruit is mammillate, and of two kinds externally, 

 either of an orange colour, or of a lemon-yellow, and 

 possibly also of a fawn colour.* 



Then are these intermediate forms the result of 

 natural crossing ? Without having made direct and 

 careful experiments, I cannot say whether the mingling 

 of the orange and lemon, by crossing, is even possible. 

 All my observations, and the records of others incline 

 me to the conclusion that the different varieties of 

 citrus do not readily cross. Plants raised from seed, 

 however, are said to vary within certain limits, even 

 without crossing. The Seville orange, the khatta, 



* Vide pi. 259, for a still more curious apparent mixture of 

 orange and citron in one fruit. (?) 



