504 
Stiles. — The Podoca rpeae . 
Among the Equisetales in Palaeostachya the sporangiophores are found 
on the upper side of the sporophyll, while in Cingularia the sporangia 
are below the sporophylls. In this case the value of the analogy is 
perhaps lessened to some extent through the doubt which exists as to 
the correct reference to the Equisetales of Cingularia ; the argument, 
however, still holds good if that genus really belongs to the Spheno- 
phyllales. Moreover, if the microsporophylls and megasporophylls are 
actually homologous with one another, and all workers on the Podocarpeae 
are agreed that the female scale is actually a simple sporophyll, a shifting 
of the sporangium to the other side of the sporophyll must have taken 
place in the evolution of one or other kind of sporophyll ; unless, indeed, 
the homosporous ancestor bore sporangia on both sides of the sporophyll, 
a state of affairs which, having regard to the relation of sporangia to 
sporophylls in all orders of the Pteridophyta, one must regard as extremely 
unlikely. 
Nor is the possession of the seed-habit in the Conifers to be regarded 
as evidence against the Lycopodialean ancestry of these forms, as Professor 
Seward and Miss Ford have already pointed out . 1 The seed-habit had 
already been evolved in the Lycopodiales in Palaeozoic times, as in the 
cases of Lepidocarpon and Miadesmia ; in the recent genus Selaginella , 
some approach to it appears in Selaginella apus and S', rupestris , 2 while one 
of its accompanying phenomena, the reduction of the number of spores in the 
megasporangium, occurs in several species . 3 There is thus abundant 
evidence that the potentiality of seed-production existed in this phylum as 
well as in the Fern phylum. 
The vascular anatomy of the sporophylls affords an interesting com- 
parison between the two orders. In the Lycopods the sporangium supply 
consists of a single medianly placed vascular bundle. In the living genera 
there is no special sporangial supply apart from this, but in some species of 
the genus Lycopodium there is evidence of the remains of a median 
sporangial supply given off from the upper surface of the sporophyll bundle . 4 
This is the state of affairs which exists in the young state of the mega- 
sporophyll in Saxegothaea and Microcachrys ; 5 later it is much modified in 
the former case owing to the development of ovular bundles which attach 
themselves laterally to the sporophyll bundle. In the more modified 
fructification of Dacrydium Franklini the central median bundle of the 
ovular supply is lost, and the lateral bundles alone form the ovular supply ; 
in the species of Podocarpus examined these two lateral supply bundles are 
carried down into the axis of the strobilus independently of the sporophyll 
bundle. That this condition is to be accounted for by the greater relative 
1 Seward and Ford (’06), p. 394. 2 Lyon, F. M. (’01). 
8 Lyon, 1. c., p. 138 ; Mitchell (’10), p. 24; Sykes and Stiles P10), p. 529. 
4 Sykes ('08), p. 43. 5 Thomson (’09 2 ), p. 349* 
