21 
Emms,— The Morphology of Agathis australis . 
goales. They stand off, likewise, sharply from the other Conifers. Yet in 
essential underlying features they clearly belong to the latter. Starting 
with some ancient coniferous stock specialization has followed rather 
different lines in the araucarian branch from that taken in others. Yet 
many of the same tendencies have prevailed in both, as an attempt has been 
made to show above by comparing some characters of the recent groups 
Taxodineae and Cupressineae, especially of the genus Sequoia. 
If then this tribe, though somewhat apart from other Conifers, yet dis- 
tinctly goes together with them on the ground of gametophytic morphology 
and of embryology, what additional evidence of this position does its mature 
sporophyte afford ? In anatomy, perhaps the most critical features pointing 
to a distinctness of the Araucarians from other Conifers are the lack of xylar 
resin canals and of bars of Sanio ; and in morphology the question of the 
underlying structure of the megasporophyll is of the greatest importance. 
Professor Jeffrey is about to announce the discovery of bars of Sanio and 
of resin canals, as well as of abietineous pitting in the xylem of araucarian 
cones. Thus the most conservative region of the sporophyte in this tribe 
proclaims its origin from a stock possessing characters which have been 
retained by the Abietineae. 
The morphology of the ovulate strobilus of the Coniferales has been 
a much debated subject. It is apparently now clear, however, that the 
megasporophyll of the Abietineae represents a modified axillary branch, 
homologous with the ‘ short shoot ’, placed in the axil of a bract. The 
relations of the two structures are very nearly the same as those of their 
homologues upon vegetative branches. The vascular supply is similar. 
The bract, as in all Conifers, receives a bundle from the axis with xylem 
and phloem arranged as in any leaf. The vascular supply to the sporophyll 
has the position of the xylem and phloem inverted. It arises like that of 
an axillary structure, — that is, it is formed by the immediate fusion of two 
strands departing separately from the centra lcylinder of the cone above the 
origin of the bract bundle. Text- figs. 75 to 78 are diagrams to show the con- 
dition common to the Abietineae, 75 giving the method of origin of the two 
strands found in 76. Text-fig. 77, at the very base of the scale, shows the 
bract, slightly fused, and the bundle of the upper series dividing into 
three ; 78 shows the small free bract, and the scale with its strong series, 
also the ovular supply bundles passing to the two ovules. 
Within the Abietineae these two companion structures have undergone 
very little change, both retaining their identity. The bract is less prominent 
in some genera, and is slightly fused at its base to the scale (Text-fig. 77). 
The vascular supplies of the two are quite distinct throughout. Fusion of 
these two elements, which is only suggested in this tribe, becomes a promi- 
nent feature of the Taxodineae and Cupressineae. In their evolution from 
abietinean stock the double nature of the elements of the ovuliferous cone 
