25§ 
W. T. Saxton. 
It is not possible to indicate fully the various divergences, con¬ 
vergences and relationships of any phylum in a diagram confined to 
two dimensions, but a general idea of Gymnosperm phylogeny 
according to the views here put forward is given in the accom. 
panying chart. 1 It must, however, he admitted that the data are at 
present insufficient to establish the true sequence of Gymnosperm 
phylogeny with any certainty. 
For the sake of simplicity, and to avoid repeated duplication of 
numerous references, the sources of information have not been 
individually acknowledged in the preceding account. These sources 
are, however, given in the following list of references; the list is by 
no means intended to be a complete bibliography of Conifer 
literature, but an attempt has been made to include all the important 
sources of information and opinion, in regard to the immediate 
subject of the essay; references to purely anatomical work have 
not, as a rule, been included. 
It may be added that a discussion of this kind could be almost 
indefinitely lengthened if all the minor characters which may be 
used in certain cases for purposes of sub-division were taken 
into account; such characters have been often purposely passed 
over for the sake of brevity, and in ol der not to obscure the main 
question. For a similar reason sub-division has not been carried 
further than the families and sub-families; opinions have differed 
far less as to the smaller sub-divisions, than in regard to the main 
outlines of classification, and there seems no objection to the 
continued use of the smaller groups of genera, limited as at present; 
in the opinion of the writer, however, there is at present no justifi¬ 
cation for grouping together those genera of the Cupressoi'dete (as 
here defined) formerly united in the tribe Taxodieie, in any sub¬ 
division of a higher order than a sub-tribe, and even this seems 
unnecessary ; the Cupressoidese form a very well defined sub-family, 
and, the number of genera being fairly small, it is not necessary for 
purposes of convenience to group them into smaller alliances of an 
artificial character. 
In conclusion the writer wishes to express his thanks to 
Professor H. H. W. Pearson, and to Professor A. C. Seward, for 
criticism in regard to certain points. 
1 Gymnosperms other than Conifers are included in the Chart, but are 
arranged more or less in accordance with widely accepted views, as put 
forward— e.g., in Coulter & Chamberlain’s Morphology of Gymnosperms. 
Botany School, 
Cambridge. 
June, 1913. 
