182 ORIGIN OF CULTIVATED PLANTS. 



and by a thinner rind. They differ from lemons and citrons 

 in their pure white flowers ; in the fruit, which is never 

 elongated, and without a nipple on the summit ; in the rind, 

 smooth or nearly so, and adhering but lightly to the pulp. 



Neither Risso, in his excellent monograph of Citrus, 

 nor modern authors, as Brandis and Sir Joseph Hooker, 

 have been able to discover any other character than the 

 taste to distinguish the sweet orange from more or less 

 bitter fruits. This difference appeared to me of such 

 slight importance from the botanical point of view, when 

 I studied the question of origin in 1855, that I was 

 inclined, with Risso, to consider these two sorts of orange 

 as simple varieties. Modern Anglo-Indian authors do 

 the same. They add a third variety, which they call 

 Bergamia, for the bergamot orange, of which the flower is 

 smaller, and the fruit spherical or pyriform, and smaller 

 than the common orange, aromatic and slightly acid. 

 This last form has not been found wild, and appears to 

 me to be rather a product of cultivation. 



It is often asked whether the seeds of sweet oranges 

 yield sweet oranges, and of bitter, bitter oranges. It 

 matters little from the point of view of the distinction 

 into species or varieties, for we know that both in the 

 animal and vegetable kingdoms all characters are more 

 or less hereditary, that certain varieties are habitually 

 so, to such a degree that they should be called races, and 

 that the distinction into species must consequently be 

 founded upon other considerations, such as the absence of 

 intermediate forms, or the failure of crossed fertilization 

 to produce fertile hybrids. However, the question is not 

 devoid of interest in the present case, and I must answer 

 that experiments have given results which are at times 

 contradictory. 



Gallesio, an excellent observer, expresses himself as 

 follows : — " I have during a long series of years sown pips 

 of sweet oranges, taken sometimes from the natural tree, 

 sometimes from oranges grafted on bitter orange trees 

 or lemon trees. The result has always been trees bearing 

 sweet fruit ; and the same has been observed for more 

 than sixty years by all the gardeners of Finale. There 



