The Classification of Conifers. 251 
Sciadopitys becomes an important link between the Abietoidese and 
the Cupressoideae (in the sense in which those sub-families are defined 
below), while it simply constitutes an insoluble problem when 
associated with Taxodium, Sequoia and other genera, as has usually 
been the case. Phylogenetically Sequoia still remains something of 
a problem, but one of which possible solutions can be quite reasonably 
suggested when it is realised that the position of the genus is an 
isolated one. 
Whether these two genera are made the types of a tribe or of 
a sub-family is of very small importance, and is perhaps not much 
more than a convention, but it has seemed to the writer most in 
accordance with our present knowledge of these genera to regard 
them as the representatives of sub-families ; the chief reason for 
this view is that the differences between each and its nearest allies 
are of very much the same order as those between the families, while 
to consider them as tribes only, implies differences of a different, and 
lesser, order than those used to delimit the families. The only 
other sub-family, not generally recognised, which the writer con¬ 
siders should be distinct is the Callitroi'deae, including Widdvingtonia, 
Callitris and Actinostrobus ; the claims of this alliance to tribal 
distinction have been repeatedly urged by the writer, and the only 
alteration now suggested is to raise the rank to that of a sub-family, 
on precisely the same grounds as in the case of Sequoia and 
Sciadopitys. 
It has been assumed in almost every publication dealing with 
the classification of the Conifers, that within the Coniferales two 
main families are met with, and two only; but a study of the 
various schemes reveals the surprising fact that these two families 
are made up by combining the various tribes in almost every 
conceivable way. Thus Strasburger, whose view has probably come 
to be regarded as the orthodox one in this respect, combines Taxads 1 
and Podocarps as Taxacese, and the rest of the Conifers as Arau- 
cariaceae. Essentially the same arrangement, though often with 
different names, has been followed by Eichler in Germany, by Coulter 
and Chamberlain in America, and by Masters in England. Beissner 
includes Podocarps (exclusive of Phy lloclad us), Avaucavians (including 
Cunninghamia and Sciadopitys), and Abieteae in one “Series”; 
Cupressese, Taxodieae and Taxeae in another. Hansen, a year later, 
followed Beissner’s grouping exactly, while very recently Stiles has 
argued in favour of Beissner’s scheme, though his tribes are 
1 This, as in all the older classifications includes Ginkgo, now generally 
recognised to belong to a quite different phylum. 
