IMPREGNATION OF THE SEED, CHAP. VII. 



Passage of But admitting that the pollen is conveyed to the 

 through stigma by the means above stated, how is it thence 

 the style. con d uc t ec | to the ovary ? It was at one time gene- 

 rally supposed that the pollen is conducted from 

 the stigma to the ovary by means of a longitudinal 

 canal perforating the style. This canal is distin- 

 guishable in many of the liliaceous plants in which 

 it seems indeed to constitute the passage of the 

 pollen particularly from the phenomenon of the 

 Amaryllis formosissima, the fluid exuding from 

 the stigma of which returns again through the per- 

 foration of the style tinged with yellow, the colour 

 of the pollen. But the existence of the canal in 

 question, though distinguishable in the Amaryllis 

 formosissima, and other liliaceous plants, cannot 

 be admitted as a universal property of the style, at 

 least it cannot be detected. And if it is so very 

 fine as to escape all observation, then it could not 

 admit the particles of pollen, which are in some 

 cases comparatively large, as in Marvel of Peru ; the 

 pollen of which exceeds the style itself in diameter, 

 and could not consequently be admitted by a cen- 

 tral canal. 



But in order to effect the impregnation of the 

 seed it is not necessary that the particles of pollen 

 should enter the style entire. The finer part of 

 their contents is sufficient, and is indeed the only 

 effective part in the act of fecundation : so that 

 whether we regard it as a subtle and elastic vapour 

 with Grew, and Adanson ; or merely as an oily 



