OBJECTIONS TO THE THEORY 295 



physiological signification; but Dr. Hooker informs me 

 that within the same ovarium, the upper ovules alone 

 in some cases, and in other cases the lower ones alone 

 are fertilized; and he suggests that this probably depends 

 on the direction in which the pollen-tubes enter the ova- 

 rium. If so, the position of the ovules, even when one 

 is erect and the other suspended within the same ova- 

 rium, would follow from the selection of any slight de- 

 viations in position which favored their fertilization and 

 the production of seed. 



Several plants belonging to distinct orders habitually 

 produce flowers of two kinds — the one open of the ordi- 

 nary structure, the other closed and imperfect. These 

 two kinds of flowers sometimes differ wonderfully in 

 structure, yet may be seen to graduate into each other 

 on the same plant. The ordinary and open flowers can 

 be intercrossed; and the benefits which certainly are de- 

 rived from this process are thus secured. The closed 

 and imperfect flowers are, however, manifestly of high 

 importance, as they yield with the utmost safety a large 

 stock of seed, with the expenditure of wonderfully little 

 pollen. The two kinds of flowers often differ much, as 

 just stated, in structure. The petals in the imperfect 

 flowers almost always consist of mere rudiments, and the 

 pollen-grains are reduced in diameter. In Ononis col- 

 umnse five of the alternate stamens are rudimentary; and 

 in some species of Viola three stamens are in this state, 

 two retaining their proper function, but being of very 

 small size. In six out of thirty of the closed flowers in 

 an Indian violet (name unknown, for the plants have 

 never produced with me perfect flowers), the sepals are 

 reduced from the normal number of five to three. In 



