52 



MAINE STATE COLLEGE 



IV 



By careful selection we have secured tomatoes with relatively 

 very few seeds ; and Professor Bailey reports absolutely seedless 

 fruits.* It is very doubtful, however, if these fruits can be re- 

 garded as any tiling but variations. The habit of tlie plant lias 

 become so modilied tliat llie inlhience of tlie pollen in stimulating 

 o-rowth is stronger than its fecundating power. In none of the 

 plants bearing relatively seedless fruits, was there an apparent 

 lack of pollen. 



A further instance of the nnodification of the form 

 of fruit as a result of pollination, was observed with 

 English cucumbers. As a rule, in cases of artificial 

 pollination, if the fruit developed at ail, the apex 

 was much enlarged and perfect seeds were develop- 

 ed, — these seeds usually extending about one third 

 of the length of the fruit. This result I have 

 found to be almost invariable with some varieties, 

 — notably the " Telegraph ", of which an example 

 is shown in Figure 14, This peculiarity of form 

 is the usual result of pollination in other varieties 

 also, but it is not invariably the case, and Professor 

 Bailey regards the irregular form as "an expression 

 of plant variation, rather than a result of particular 

 treatment."! Certain individuals maybe more sus- 

 ceptible to the influence of pollen than others, but 

 as the variation is traceable directly to the action 

 of pollen in the impregnation of the ovules, the sub- 

 ject may properly be considered in this connection. 

 At the present time, however, we can only say that 

 as a rule this particular variation is induced by the 

 action of pollen. The reason is yet to be deter- 



Fif. 14. • -1 



Telegraph, mined. 



Artificially Pollinated. 



In other words, the reason for the failure of seeds to develop 

 throughout the length of the ovary in the long English cucum 

 bers, when pollen is applied to the stigma, is as yet uncertain. 

 It appears probable, however, that the explanation lies in the ex- 

 treme length of the ovary and the consequent inability of the pollen 

 tubes to penetrate so far. There has been a variation in the ovary 

 without a corresponding variation in the pollen. The amount of 



%\% 



*Rep. Cornell Univ. Exp. Sta. 1891, 55. 

 tBailej', Bui. 31 Cornell Univ. Exp. Sta. 137. 



