PHYSIOLOGY... 30F 
is therefore not quite mistaken, when he compares 
the growth of plants to a contraction and expansion ; 
an idea which Wolf already has endeavoured to prove. 
§ 285. 
The flower is likewise, as all the other parts of 
plants, formed from air vessels, which, as soon as 
the first rude sketch, as it were, of the flower exists, 
are already observable. Linné’s opinion with re- 
gard to the formation of the flower, is quite erro- 
neous. He considered the pith of a plant, which 
he believed to be of equal importance with the spi- 
nal marrow of animals, as the sole formative organ. 
in the whole vegetable kingdom. Vegetation in ge- 
neral, according to his opinion, went on by means 
of the pith. The seed itself was a small piece of 
pith, which separated from the whole, on purpose 
to go through the same revolutions as the old plant 
had done. But he proceeded still further, and 
ascribed to each part of a plant a certain peculiar 
power in forming one part of the flower. The calyx 
was formed by the bark, the corolla by the inner 
bark; the stamens were formed by the wood, and 
the pistils by the pith. He carried this hypothesis 
still further, by asserting, that in ligneous plants 
each branch required five years for the final evolu- 
tion of the flower, and that each year something was 
added to the future flower. In the first year, for 
instance, the scales, (sguamae), are formed, when the 
branch is shooting out from the bud; in the second 
year the calyx; the corolla in the third; in the 
fourth the stamens; and in the fifth the whole, for 
Wee the 
