494 
Stiles.— The Podocarpeae. 
appearance, and with its reproductive shoots bearing male and female cones, 
with the sporophylls spirally arranged. On the upper parts of the repro- 
ductive shoots there was a gradual transition between foliage leaves and 
sporophylls. Each microsporophyll bore two sporangia, while each mega- 
sporophyll bore in its axil a single erect ovule surrounded by a single 
integument. 
From this primitive type we have had two main lines of development. 
In Pherosphaera there has been reduction in the size of the leaves and in 
the number of sporophylls in the cone ; the megasporangium has, however, 
retained its primitive character. In Phyllocladus the reduction has proceeded 
still further, and there has occurred the special development of stems into 
phylloclades, physiologically to replace the leaves, here reduced to small 
insignificant scales. The ovule has also been clothed by a second integu- 
ment completely surrounding the inner. The prothallial tissue in the male 
gametophyte consists of two or occasionally three cells ; while in the small 
number of archegonia in the female gametophyte we perhaps have 
another reduction phenomenon. Owing to our absolute ignorance of 
the gametophytes of Pherosphaera , it is impossible to say whether in 
this respect Phyllocladus is further reduced than its otherwise more 
primitive relation. 
Along the other line of descent we have intercalary growth taking place 
at the base of the megasporophyll, resulting in the removal of the ovule 
from the cone axis, and in many cases causing also its greater or less 
inversion. Probably correlated with this is the development of the incom- 
plete outer integument or epimatium, for this is not present in any other 
phylum of Conifers, nor in the other Podocarpean line of descent. 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 Micro- 
cachrys suggests the former, while a somewhat older state of Dacrydium 
cupressinum suggests the latter. The most primitive genus of this phylum 
is Saxegothaea , where the cone is still well developed. This is a somewhat 
smaller structure in Microcachrys , but is still a compact cone. The latter 
genus has also suffered reduction in its leaves and in the suppression of 
resin canals in the stem, though these are still present in the leaves and 
megasporophylls. 
In Dacrydium Franklini the megasporangiate strobilus consists of about 
eight megasporophylls separated by appreciable internodes. The ovule is 
partially inverted, and the incomplete outer integument or epimatium is 
present, as in Saxegothaea and Microcachrys . As in the latter genus, resin 
canals are absent from the stem, but are present in the leaves and mega- 
sporophylls ; in fact the internal structure of this plant, especially as regards 
the megasporophyll, is remarkably like Microcachrys . Curiously enough, 
both are limited in their distribution to Tasmania, though one is a small 
