374 On the Genealogy of Plants. [June, 
from the Araucarian pines to the yew trees, such progress is well 
marked, and in Sa/isburya, the Japanese Ginkgo, which is related 
to the yew, the foliage comes at length to closely resemble that 
of many exogenous Angiosperms. The suspicion has even been 
expressed that all the genera of the Conifere may not have 
sprung from the same parent stock. 
The origin of the Dicotyle, which constitutes the chief problem — 
in the genealogy of plants, is thus seen to be one which, while it 
admits of several possible solutions, nevertheless, in the present 
state of science, certainly admits of no positive solution. What- 
ever hypothesis we adopt, if we suppose a monophyletic origin for 
all plants, the derivation of both branches of the Angiosperme 
from this common root will involve what may be thought to be a 
violent assumption. If the endogenous Angiosperms have 
developed out of the Cycadacee and the exogenous Angio- 
sperms out of the Guetacee, it requires some stretch of our 
credulity, in view of the bad repute into which all alleged “ anal- 
ogous ” organs have in recent times fallen, to admit that the 
closed ovary, so identical in the two classes of plants, could have 
been arrived at from two such independent sources. To avoid 
this difficulty, which no one knows better how to appreciate, 
Prof. Heckel suggests the probability that the Angiosperms as’a 
class were first developed from the Guetacee, and that subse- 
quently, they subdivided into the monocotyledonous and the 
dicotyledonous branches.! But with due deference to so high an 
authority, it is submitted that this would involve a still more 
violent assumption, viz: that an endogenous structure was derived 
from an exogenous one. Besides, we fail to find a single fact 
either in morphology or in palaontology to support this hypoth- 
esis. Again, if we seek to trace the genealogy of the Dicotyle back 
through the Monocotyle to the Cycadacee, we are driven to the 
equally forbidden presumption that the exogenous structure of 
the Dicotyle and of the Conifere and Guetacee was independently 
reached. There is, therefore, no serial line by following which 
_ all these difficulties can be escaped. a 
Those to whom all these instances of so-called “teleology 
present no serious obstacle, may even find satisfaction in the con- 
ception that not only are the Conifere descended from two) ~ 
different parent stocks and the Gnetace@ from still a third, but 
1Schépfungsgeschichte, Aufl. 5, Berlin, 1874, S. 430. 
