MONOGRAPH OF THE GENUS PYRUS. 191 



exterior flesh as calyx, Professor Decaisne (no doubt cor- 

 rectly) regards it as mainly receptacle or axis, an hyiian- 

 thium which in common pears is largely a hypertrophy of the 

 peduncle, after the fashion of Anacardium. 



In the proper Pear genus, the ovules never exceed a single 

 pair ; this should therefore enter into the generic character. 



" Theophrastus had already remarked that the older the 

 Pear-tree, the more prolific, and every day's experience con- 

 firms the justice of this observation." The gritty grains or 

 lignified cells which are so abundant in the flesh of many 

 sorts of pears are not wholly absent from any of them. To 

 them is due the roughish surface of the skin, as contrasted 

 with the smooth skin of ajsples. It is curious to remark that 

 Meyen, in his " Pflanzen-Pathologie," considered the gritty 

 grains to be a disease which attacked pears and quinces. 



It appears that pear-growers are able to produce fruits of 

 abnormal size by supporting the growing pear from under- 

 neath, instead of allowing it to hang on the peduncle. M. 

 Decaisne has seen Poires de Livre of a kilogram, Glou- 

 morceau of 600 grams, and a Chaumontel of 700 grams 

 weight, produced in this way. 



The testa of all Pomaceous seeds is smooth and more or 

 less mucilaginous, except of a Photinia, in which it is retic- 

 ulated. The cotyledons are accumbent relative to the rhaphe, 

 except in a Photinia, Cotoneastei', Pyracantha (^Crataegus 

 PyracantJia, Pers.), and Eriobotrya, in which they are incum- 

 bent. At first there is a thin layer of albumen, which disap- 

 pears at maturity of the seed. 



Pears are commonly grafted upon a Quince stock. But it 

 is confidently asserted, and generally supposed, that there are 

 more than forty varieties which absolutely refuse this union, 

 and which are therefore managed by subgrafting upon a Pear 

 stock of a proper sort which has itself been engrafted upon 

 the Quince. But, as Professor Decaisne remarks, horticul- 

 turists are too apt to generalize their impressions and to limit 

 nature to the narrow horizon of their own practice. Upon 

 the first trial of the experiment under his own observation, he 

 succeeded with twenty of these antipathetic varieties without 



