1885.] How the Pitcher Plant got its Leaves. 577 
one attracts the insects for purposes of fertilization, the other, 
by its imitative. powers draws the visitor to it and is thus 
enabled to feed itself. Nor is such a suggestion an unreasonable 
one when the highly specialized condition of the plant is con- 
sidered. If once a hint in that direction showed itself, and any 
benefit was thereby derived, it may be considered as certain that 
the direction would be persevered in until both leaves and flowers 
had departed very far from the original and normal type. This 
is exactly what has happened. 
Coming finally to the geographical distribution of the order, 
the facts show plainly how one could have been derived from the 
other. The original home of all was most likely in South 
America, where one species still lingers. This original form may 
be imagined as conveyed from its place of origin to the south 
coast of what is now the United States, most likely by means of 
the Gulf Stream. Finding a suitable place for living, the some- 
what changed conditions would have modified the emigrant into 
a plant with a leaf like S. purpurea, This once fairly established 
spread all over the country where there were favorable condi- 
tions for its growth. If we imagine this dispersion to have been 
during the continuance of the Tertiary period, there would have 
been ample time for great modification to take place. Then it 
was, in all likelihood, that the Darlingtonia began to develop in 
its own way. After a long period of time the Tertiary epoch 
was brought to a close. A great change came over the face of 
the country, and many of the intermediate forms between Sarra- 
cenia and Darlingtonia became extinct. Change in climate and 
in conditions produced by the glaciers which covered the country 
at one time was an efficient agent of extinction. At the same 
time the unextinguished forms would have continued to become 
modified in various ways until they became as they are now 
found. 
The history of this one family, peculiarly circumstanced as it 
is, shows the possible origin of a number of forms from one 
common ancestor, different though they are from each other at 
present. In every part can be traced the werkings of evolution. 
In leaf and in flower the steps can be followed. Even in the 
geographical distribution of the living species it can be seen. In 
some. families of plants the steps are not so plain because encum- 
bered by a larger number of generic and specific forms; but 
