70 Sinnott . — Tife Morphology of the 
primordium, and the single-scaled series have arisen through either the fusion 
of the two appendages or the abortion of one of them. In the ascending 
series from the Abietineae to the Taxodineae and Cupressineae we may 
observe the gradual fusion of bract and scale, which usually results in the 
complete dominance of the scale and the almost entire disappearance of 
the bract and its vascular supply. In a few cases, however, notably A thro- 
taxis and Cunninghamia y where it is the bract which becomes dominant, 
the scale is so much reduced that its vascular system is represented by only 
a few small strands, sometimes only one, given off from the ventral face of 
the bract bundle, and serving merely to supply the ovules (Diagram 8, f). 
This condition of affairs is so precisely similar to that which we find in 
Saxegothea on the one hand, and in certain of the Araucarineae on the 
other, that it provides an illuminating suggestion, noted by earlier investi- 
gators, as to how the features of strobilar anatomy in these two groups have 
arisen. The hypothesis that in Saxegothea and the Araucarineae, as well 
as in Cunninghamia , the simple scale has been evolved by reduction from 
a more complex double one seems to the writer to be the most plausible 
yet * suggested. Eames (3) in a contemporaneous paper brings forward 
strong evidence for the derivation of the araucarian cone-scale from a 
primitively double structure, and the results of anatomical investigations 
on the cones of Saxegothea , Microcachrys , and Phyllocladus seem to indicate 
that the simple scale in these forms has been evolved from the double 
strobilar appendage of Podocarpus , and that this genus is the most primitive 
of the family and stands close to the Abietineae. 
This hypothesis, which instead of deriving the Podocarpineae from the 
Araucarineae considers them to have descended from the primitive Abietineae 
through forms somewhat resembling those found in the living genus Podo- 
carpus , is supported by abundant evidence from our comparative study of 
the reproductive structures of the families in question. 
In both Podocarpus and the Abietineae the female cone is composed 
of subtending sterile bracts, each provided with a single strand, and almost 
or quite free from the axillary ovuliferous structure. In both, the vascular 
supply of the latter arises as two separate bundles, each derived from a side 
of the bracteal gap, which approach each other by their adaxial ends, become 
oriented inversely to the bract bundle, and fuse. In both, this single fused 
bundle tends strongly to divide into three when it enters the base of the 
ovuliferous scale or epimatium. In most species of Podocarpus two distinct 
ovular bundles are given off from the main supply just as in the Abietineae, 
and instead of displaying inverse orientation these are usually concentric, 
a condition which Radais also observed in the ovular bundles of the 
Abietineae. In fact, it seems doubtful if the inversion in orientation of the 
ovular supply, ‘ the second inversion,’ is at all common. 
The main cone of Podocarpus and of its family is almost identical with 
