FECUNDATION. 179 
Nehemiah Grew, a learned English fellow of the Royal Society of 
London, who published in 1682 an Anatomy of Plants, above all 
Jacques Camerarius, a German botanist, born at Tubingen, showed 
the precise use of the two essential parts of the flower, and the 
part that each plays in producing the fecundation of germs. Ina 
letter now become celebrated, De sexu plantarum, published in 
1694, Camerarius completely proved the great fact of the exist- 
ence of the sexes in plants just as in animals. This discovery 
made an impression on the minds of naturalists ; it was, in fact, one 
of the most striking victories which natural science had obtained. 
After the labours of Camerarius, the existence of sexes in 
vegetables was generally admitted. Tournefort was incredulous, 
but Sebastien Vaillant, one of his most brilliant pupils, publicly 
professed in the Jardin des Plantes at Paris the theory of separate 
sexes in plants. In 1735 the celebrated Linnzus rendered it 
popular by basing on the sexual characteristics of vegetables his 
vast and admirable system of clas- nie 
sification, the importance of which 
we shall appreciate further on. 
The pollen having been recog- 
as the matter which fecun- 
dates the ovary, the next question 
was to discover in what manner 
the graius of pollen produced the 
fecundation of the vegetable germ. 
It was at first thought that the 
grains of pollen simply opened on 
the stigma, and that the granules 
which they contained, being absorbed 
by the stigma, went to form the 
embryo, or concurred in its forma- 
tion. It was the most natural opi- 
nion to form & priori, yet observation 
has since proved that a much more 
Ba conte process takes place. : 
n 1823 Amici, an Italian natural ot nein 
Dimthic wile ducing te 
African Purslane-tree, perceived that the grains of pollen, far 
N 2 
