294 



healthy until injured by the autumn frosts. At A we see a normal woody 

 branch ; at 5 a branch, the terminal bud of which is swollen up to a seedless 

 fruit ; at C is shown a fruit grown from a lateral bud with primordia of 

 core ; n is the scar of a fallen leaf ; s an undeveloped lateral bud ; k a per- 

 fectly matured leaf bud on the fruit stem ; sch scale-like leaf on this stem ; 

 at (J are the normally extended vascular bundle fibres, arranged about the 

 compartments of the core (/) enclosing the rudimentar}' ovules. At c are 

 visible the dried remains of the calyx and at st the branches of the style. 



This case differs from the one described by Burbidge and from most 

 others described as yet, in that the fruit is the product of the buds of the 

 current, not of the previous year. It is not rare for the pear to bear 



occasional fall flowers. They can, in 

 fact, arise from buds set the previous 

 }ear, as is often stated, but, as yet, I 

 have had opportunity to observe only 

 such blossoms as were produced on 

 the branches of the current year, ma- 

 tured in the summer, a fact which 

 could be determined easily from the 

 wood ring of the branch bearing the 

 fruit. The proleptic blossoms had, 

 with the relatively scanty nutritive 

 supply and the short time granted 

 them for development in the fall, 

 naturally little opportunity to develop 

 the parts of the cortex into well fla- 

 vored fruit flesh. This explains, on 

 the one hand, the lack of size and, on 

 the other, the lack of flavor of the 

 pears here described. If the fruit buds 

 had not been stimulated by the un- 

 usually increased supply of water at 

 the then autumnal season, they would probably have yielded perfectly 

 normal fruits the following year. 



While the fruit remained seedless in this case, because in the proleptic 

 development the accumulated building materials are insufficient, other cases 

 also occur in which enough material is present, but is utilized in some other 

 way because of the destruction of the normal embryo. Thus Miiller- 

 Thurgau^ states that pears whose carpel layers had been destroyed by a late 

 frost, produced fruit then exhibiting in place of a core a hollow chamber in 

 which tissue excrescences had grown out from the side wall. 



The appearance of seedless fruits is, therefore, to be treated primarily 

 as a question of food supply. The organic building substances are not 



PMg. 36. Seedless Pear. 



1 Miiller-Thurgau, H., Eigentiimliche Frostschaden an Obstbaumen und Reben. 

 X-XII. Jahresb. der Deutsch-schweizer. Versuchsstat. Wadensweil, 1902, p. 66. 



