280 BOTANICAL GAZETTE [OCTOBER 
megasporophyll in the Abietineae, but in the Araucarineae they 
consider it as a simple structure which may or may not be homol- 
ogous with the double structure in other conifers. They regard 
the Araucarineae as one of the oldest if not the oldest of the coni- 
fers. They favor the lycopod origin of the Araucarineae and set 
them apart under the name of Araucariales. 
THOMSON (8) in 1909, in a paper on Saxegothaea and Microca- 
chrys, admits that the brachyblast theory is inevitable in the 
Abietineae, Taxodineae, and Cupressineae. Accepting BRAUN’S 
conception that the scale in the Abietineae represents the first 
and only two leaves of an abortive shoot, which have fused by 
their adaxial margins, he says: : 
The first inversion is explained and the ovules in the group are borne on 
the morphological under side. The second inversion is analogous to the single 
one in Saxegothaea and of the nature of a sporangial supply. There are then 
two great groups of conifers from the standpoint of this study, the simple 
and the complex scaled series. Both forms have the ovules on the physiologi- 
cally upper surface, a position rendered almost imperative by the necessities 
of the seed habit. This position however has been attained in two very differ- 
ent ways. 
STILES (5) in 1912 investigated several species of Podocarpus. 
He concludes that the original position of the ovule was erect and 
axillary as in Pherosphaera, but that owing to growth of the scale 
at the base of the sporophyll it has been carried away from the 
axis. As a result it has become inverted, and correlated with the 
inversion is probably the development of an incomplete epimatium. 
Whether this epimatium is an outgrowth of ovular or sporophyll tissue 
it is at present impossible to say. The evidence of development in Saxegothaea 
and Microcachrys suggests the former, while a somewhat older state in Dacry- 
dium cupressinum suggests the latter. 
In the latter form the ovule is borne on the epimatium, while 
in Podocarpus the epimatium has elongated into a stalk. The 
development of a strong and independent vascular supply in the 
epimatium he thinks is the result of a required need of a larger 
ovule. The epimatium in the podocarps and the scale in the Abie- 
tineae are homologous, but both are new structures. Both these 
complicated structures have been derived from a simple sporophyll. 
