34 E antes . — The Morphology of Agathis australis . 
course. This variable condition might be expected in a minute bundle 
that follows the short twisting reversed course it usually follows. Hence it 
is believed that no sound argument can be based on the inversion of the 
ovular supply. 
From comparative and structural evidence it seems, therefore, that the 
apparently simple cone scale of Agathis is really of compound nature, and 
represents the double structure of the abietinean cone. The Araucarians 
are thus Conifers , even though they have progressed far along a different 
line from that followed by the other groups. With Mr. Sinnott’s (11) 
demonstration of the similar nature of the cone scale of the Podocarpineae, 
it becomes evident that the female cones of all the Conifers are strictly 
homologous. And hence, since those forms in which the twofold nature is 
hidden are either — as the Taxodineae — admittedly recent, specialized 
derivatives of such a double-unit stock, or seem clearly to be such when all 
evidence is carefully considered, the primitive Conifers must have possessed 
this type of cone. And the Abietineae in retaining it are thus representa- 
tives of ancient, ancestral forms. The unity of the Coniferales as a natural 
group seems to be established, and the writer cannot too strongly dissent 
from the opinion expressed by Seward and Ford (10), that the living and 
extinct Araucarians should form a subdivision of the Gymnosperms, the 
‘ Araucariales \ 
From the evidence presented by the study of the morphology of 
the female cone, the Araucarians occupy the same phylogenetic position as 
is suggested by their gametophytes and embryos — a highly specialized 
branch of the Conifers derived far back from some stock possessing abie- 
tinean characters. Vestiges of features possessed by this primitive stock are 
still to be found — the bars of Sanio, opposite pitting, and xylar resin canals 
recently discovered by Dr. Jeffrey, as well as the double nature of the mega- 
sporophyll. All these features have not unnaturally been almost lost during 
the long period of separation and divergent development of the araucarian 
stock. Meanwhile, as is clear from the evidence of fossils, this group 
flourished, a great series of widely variable forms inhabiting much of the 
world during the Mesozoic. Under such circumstances the few surviving 
members might well be highly specialized forms. That the same general 
evolutionary tendencies have prevailed, however, as in all Conifers, is 
evident from the similar results brought about in forms admittedly at the 
extreme end of another branch from the primitive stock — in the genera 
Cunninghamia , A thro taxis, Sequoia. 
As between the two genera, Agathis and Araucaria , the latter, as 
regards the morphology of the ovulate strobilus, is the more primitive on the 
whole, though it contains species (A. brasiliana and A. imbricata) which 
have progressed further than any species of Agathis. Too little is yet 
known of the early life-history of Araucaria to determine from that stand- 
