Stiles . — The Podocarpeae. 507 
this discussion, as exceedingly little is known about these structures in 
either Cordaitales or fossil Lycopodiales. It is worthy of note that Camp- 
bell, who is most competent to speak on this matter, says, ‘ In the character 
of the sporangium and the early development of the prothallium, Selaginella 
undoubtedly shows the closest affinity to the Spermatophytes, especially the 
Gymnosperms, of any Pteridophyte .’ 1 
The phylogenetic importance of the presence of a suspensor in the 
embryo of both Lycopods and Conifers is now considerably lessened, owing 
to the discovery of a suspensor in some of the Ophioglossales 2 and in 
Danaea? 
During the last few years there has been a growing tendency to take 
for granted the Cordaitalean ancestry of the Coniferales. The favourable 
reception accorded to this view is no doubt largely due to the acceptance 
of the Celakovskian or some similar idea of the brachyblast nature of the 
ovulate structure of the Abietineae. The Abietineae were at first the most 
prominently studied Conifers, and it was natural to explain the simple 
cone-scaled forms studied later in terms of the more complex Abietineae. 
Satisfactory evidence has, however, yet to be produced in favour of the more 
primitive nature of the double cone scale, and to the writer the evidence 
seems to point in the reverse direction, namely, to the primitiveness in the 
Coniferales of a type bearing female cones composed of aggregations of 
simple sporophylls, each sporophyll bearing a single erect axillary ovule. 
Such a type is not found to-day, the various coniferous orders having all 
departed more or less from it in different directions. This supposed primitive 
Conifer is very suggestive of the Lycopodiales, but is not reminiscent of the 
Cordaitales. Further discoveries may necessitate a modification or the 
withdrawal of this view, but the evidence at present available is, in the opinion 
of the writer, much in favour of the Lycopodialean ancestry of the Conifers. 
xvii. Summary. 
1. Vegetative Organs. In the Podocarpeae the stem in its primary 
condition contains a ring of endarch collateral vascular bundles, these in 
some, and perhaps in all, being very small. Generally there is a resin 
canal in the cortex outside each vascular bundle. 
Except in Podocarpus § Nageia the leaf-trace consists of a single strand. 
In P odocarpns nagi there is a triple leaf-trace. 
Except in Podocarpus § Nageia there is a single median vascular bundle 
throughout the length of the leaf. This strand is accompanied by two 
lateral masses of transfusion tracheides, and usually by a single resin canal on 
the under or phloem side. Sometimes this single canal is replaced by three 
1 Campbell (’05), p. 534. 
2 Lyon, H. L. (’05), p. 455 ; Bower (’08), p. 471 ; Lang (’10), p. 611. 
3 Campbell (’09), p. 691. 
