42 



EOYAL HOETIC ULTUEAL SOCIETT. 



which show a specific distinction in these different kinds of pear- 

 trees. Assuredly I should ask nothing better, for nothing is so 

 pleasing to the mind of a botanist as definite characters, those gaps 

 in the series of congeneric forms, which at the same time facilitate 

 his labour and furnish a fulcrum to his nomenclature. He is 

 satisfied when these specific, well-defined divisions agree with his 

 ideal notions of nature ; but unhappily it is not so in the group 

 of pear-trees : from the microscopic Pyrus azarolifera and longi- 

 pes we pass by an insensible transition to the Mille-au-godet, a 

 pear cultivated in the neighbourhood of St. Brieuc, which is 

 scarcely larger ; from this we arrive at the Sept-en-gueule, or little 

 Nutmeg, another variety, or rather assemblage of varieties, in 

 which the fruit varies from the size of a woodnut to that of a wal- 

 nut. At the same time a multitude of races and subraces, va- 

 rieties and variations of wild pears of all sorts of forms and magni- 

 tudes, from that of the Mille-au-godet to that of our common 

 cultivated pears ; and in these we pass from the smallest to the 

 most gigantic by an indefinite series of intermediates, in which 

 every difference of form and colour, from the Musette and Corne- 

 muse, which are so curiously elongated*, to those depressed pears 

 which have been justly compared to apples. 



How then, I say, can we lay hold of a specific character of any 

 value in an assemblage in which all the most extreme forms are 

 united by insensible and numberless gradations ? It is looking 

 for what nature has not done, and forcing her to enter into an 

 artificial category. 



To whatever hypothesis we may lean, as regards the notion of 

 a species, we cannot help seeing that it presents itself under dif- 

 ferent aspects, sometimes restricted within narrow limits, strictly 

 characterized, and not varying sensibly, but sometimes also prodigi- 

 ously broad, polymorphous, and, so to speak, divisible ad infinitum. 

 Pear-trees form no exception ; and many other genera of plants 

 offer the same profusion of secondary forms, and are an equal 

 source of perplexity to classifiers. 



Almost all pomologists, at least those who are worthy of the 

 name, have tried to classify pear-trees ; but all have failed, in so far 

 at least as they have never been able, in consequence of the inter- 



* These modifications of form in the fruit of the pear-tree recall in the most 

 striking manner those which occur in the esculent pumpkins, melons, and gourds, 

 where we see equally the fruit elongated till it becomes quite serpentine, while 

 others, on the contrary, are abbreviated and flattened at either extremity. (See 

 Naudin, Ann. des Sc. Nat. t. vi. 1856.) 



