ANEMONE VIRGINIANA, —THIMBLE-WEED. 95 
European forms, that disquisitions on their real nature have been 
made by distinguished botanists. In the “Journal of the Proceed- 
ings of the Linnzean Society, of London,” for 1860, Mr. George 
Bentham suggests that the involucre of Anemone was, originally, 
but a single leaf clasping the stem; and Professor Asa Gray takes 
occasion in “Silliman’s Journal,” of May, in that year, to show 
from the well-developed involucral leaves of Anemone Virginiana, 
here illustrated, what their real nature is. 
But we may pursue our studies further in the same direction. 
We may learn from our present species, how closely related all 
the parts of a plant are, and see very easily how one part is 
transformed from another part. We must imagine first that our 
plant may have had a branching character to a much greater 
extent than it possesses now. ‘The five petals may have been 
leaves just as fully developed as the three “involucral”’ leaves in 
our plate but for a greater arresting power of development at 
that point, in which case the central portion, now stamens and 
pistils, would have been extended to another flower-stem, and 
there would have been five axillary buds at the base of each of 
these five involucral leaves. Just this process has occurred as 
we can trace in the picture; except there were but three axillary 
buds there, and but three leaves. In the arrestation of the 
central stem, the three axillary buds were not transformed, but 
made an attempt to develop into branches, only again to be 
arrested by the reproductive force. In this case the whole 
growth is weakened, and we see was not powerful enough to 
take more than two nodes into its rhythmic grasp, making but 
two involucral leaves,—and these again so weak that no further 
axial buds could be developed. We gather, therefore, that very 
slight variations of the rhythmic force connected with the laws 
of acceleration and retardation make all the differences in struc- 
ture; and we can understand how very easily one form or 
species may be evolved from another one. Indeed, we often 
meet with variations in the normal growth of our present species 
which want nothing but permanence to be regarded good 
