1897] PHYLOGENY AND TAXONOMY OF THE ANGIOSPERMS 169 
9g. The perianth of separate leaves becomes modified by 
their fusion with one another and with other strobilar leaves 
(symphysis). The reduction (aphanisis) of the perianth is a 
modification of much less morphological significance, and is 
rarely, if ever, indicative of broad relationships. 
10. The pollen leaves show constancy in structure, dimen- 
sions, number, and_ position only within narrow limits, and 
therefore serve to define the smaller groups (families and 
tribes), but have little value as indices of broad relation- 
ships. 
11. In the symphysis of the primitive apocarpous flower 
strobilus the carpels first unite into a syncarpium, and with this 
process of fusion there is generally a progressive reduction 
(aphanisis ) in the number of constituent carpels. 
12. The extreme modification of the flower strobilus results 
in the fusion of all the constituent parts (symphysis) and their 
reduction in number (aphanisis). 
From all the foregoing we may pretty safely proceed to con- 
struct the hypothetical phylogeny of the angiosperms, to serve 
as the basis of their taxonomy. And let it be fully understood 
that this is not presented as final, or as entirely satisfactory ; it 
is merely a working hypothesis, which claims no other merit 
than that of an attempt at conformity to the suggestions some- 
times faint, sometimes doubtful, from palzontology, from embry- 
ology (ontogeny), and from morphology. That some of these 
Suggestions have been misinterpreted, or that others have been 
overlooked, is altogether likely ; but in this I must beg the 
indulgence of systematists, who may well realize the difficulties 
Surrounding the problem here undertaken. 
HYPOTHETICAL PHYLOGENY OF ANGIOSPERMS. 
The angiospermous phylum parted very early into two sub- 
classes, the monocotyledons and dicotyledons. This separation 
took place while the flower strobilus was still apocarpous, and 
before any of the strobilar leaves had undergone much, if any, 
modification. At this stage the vegetative characters of the 
