5°2 
Stiles . — The Podoca rpeae. 
1 . . . the Coniferae generally have an ectotropic mycorrhiza. It need not, 
therefore, be a matter of surprise that their Paleozoic ancestors should 
have had a similar relationship .’ 1 This of course assumes the Cor- 
daitalean origin of the Conifers, but when it is considered of what general 
occurrence among vascular plants is the presence of mycorrhiza, there 
seems no reason to regard its presence in two groups as any indication of 
relationship. 
The third point, the parallel venation of the leaves, has been dealt 
with in a previous section of this paper . 2 It was there shown that the 
evidence was in favour of the primitiveness of the single-veined leaf in the 
Podocarpeae in particular, and the Coniferae in general, so that in this case 
the evidence is directly against the Cordaitales theory. 
Finally, the last piece of evidence supposed to favour the Cordaitalean 
origin of the Conifers, that the staminate strobili and sporangia of the 
Araucarieae are like those of the Cordaitales, no more favours this view 
when the Podocarpeae are taken into consideration, than the three preceding 
pieces of evidence, for the strobili and sporangia of the Podocarpeae are 
quite unlike those of the Cordaitales. It is interesting also that Hollick 
and Jeffrey’s fossil cone, Strobilites microsporophorus , which those authors 
think may be in some ways intermediate between Araucarieae and Abieti- 
neae, closely resembles the male cone of the Podocarpeae and is also quite 
unlike the staminate strobili of Cordaites. 
Thus, if it is correct, as it seems to the author, to regard the modern 
coniferous groups as terminating a bunch of radiating lines of evolution 
from a common ancestor, it seems quite impossible to regard that ancestor 
as approaching at all nearly the Cordaitales, for in one group, the Podo- 
carpeae, the more primitive members, which exhibit undoubted resemblances 
to other groups, Araucarieae and Abietineae, as well as exhibiting other 
features which must be regarded as primitive, are unlike, in almost every 
character, the Cordaitales as at present known. 
One is therefore led to a consideration of the opposed and rather 
unpopular view of the Lycopodialean origin of the Conifers. This view 
has received strong support from Campbell 3 from a general consideration 
of the Conifers, and from Seward and Ford 4 as regards the Araucarieae 
alone. 
The most important piece of evidence in support of this view is derived 
from a comparison of the cones of the Lycopodiales and the Coniferae. In 
the Lycopodiales the sporophylls are aggregated into cones, and each 
sporophyll bears a single sporangium approximately in its axil ; in some 
cases it is true the sporangium arises from stem tissue, but generalizing it 
may be said that the characteristic of the Lycopodialean phylum is the 
1 Osborn (’09), p. 608. 
s Campbell (’05), pp. 534, 604. 
2 p. 492. 
4 Seward and Ford (’06), p. 385. 
