9 8 
Agnes Robertson. 
another is a very difficult one. The connection between Taxus 
and Torreya seems to be considerably closer than that between 
either of them and Cephalotaxus, while on the other hand Cephalo- 
taxus shews clear indications of affinity with Ginkgo. As regards 
the minute structure of the reproductive organs, Taxus and Torreya 
agree in the inequality of the sperm nuclei, and the absence or rare 
development of the ventral canal nucleus, while Cephalotaxus 
resembles Ginkgo in the equality of its sperm nuclei and the 
presence of a ventral canal nucleus. A curious little anatomical 
peculiarity shared by Cephalotaxus and Ginkgo is the presence of a 
central resin duct in the pith. 
The female “flowers” of the Taxoideae differ a great deal from 
those of other Gymnosperms. In Taxus the ovules are each borne 
in an apparently terminal position on a short leafy axis known as 
the “ primary shoot.” They are really however lateral on the 
primary shoot, being produced at the end of a much abbreviated 
secondary shoot, arising in the axil of the uppermost bract of the 
primary shoot. The growing point of the primary shoot is pushed 
to one side, so that the ovule seems to be terminal on it. Fairly 
often the two uppermost bracts of the primary shoot are fertile and 
in such cases the morphology of the structure is much clearer than 
in the reduced and more normal form (Figs. 4a and b). Torreya 
closely resembles Taxus (Figs. 5a and b). Cephalotaxus bears its 
female reproductive organs in cones, and though superficially very 
unlike Gingko, can really be more closely homologised with this 
archaic Gymnosperm than with the other Taxoideae. The cone 
consists of a number of leaves each with two erect ovules in 
its axil. 
Celakovsky’s view as to the morphology of the female “ flower ” 
in the Taxoideae, which is clearly expounded by Worsdell (10 p. 
641, etc.,) seems to me to be far better founded and more luminous, 
than the other hypotheses that have been put forward. According 
to this view “ the primary shoot of Taxus and Torreya ... .is 
the homologueof the entire plant of Cycads and the brachyblast of 
Ginkgo ; the secondary shoots are the homologues of the Cycadean 
cone and the ovuliferous axis of Ginkgo.” The cone of Cephalotaxus 
is regarded as corresponding to the “primary shoot” of Taxus or 
Torreya, or to an aggregate of the ovuliferous axes of Ginkgo with 
their subtending leaves. The belief that Ginkgo and Cephalotaxus 
can truly be homologised on these lines has been strengthened of 
late years by additional observations on abnormal “ flowers” of the 
