72 
Sinnott. — The Morphology of the 
It is in precise harmony with the view, now supported by an abundant 
evidence from many sources, that the Abietineae are the most primitive of 
all Conifers. 
It assigns a logical position to the Podocarpineae among the Coniferales, 
and does away with the necessity of dividing this otherwise homogeneous 
order into two sharply distinct series. 
It explains the wide diversity in structure found among the members 
of the genus Podocarpus as the natural state of affairs in a primitive and 
generalized genus which has not yet become fixed or stereotyped. 
It offers a reasonable explanation for the presence of the epimatium, 
as a structure homologous with the ovuliferous scale of the Abietineae, well 
developed and displaying its true nature in Podocarpus , but much reduced 
in the other genera. To consider the epimatium as a normal second 
integument which later expands into the ovuliferous scale, or to regard it 
as merely a ventral outgrowth of the sterile bract, are both theories which 
fail to explain it adequately in the presence of all the facts. 
Finally, instead of so often appealing to parallel development to solve 
the riddle, it offers a reasonable explanation for the striking similarity 
between Podocarpus , which is considered primitive, and the Abietineae, and 
on this basis makes possible the construction of a clear and consistent 
natural classification for the various genera and species of the Podocarpineae. 
Numerous intermediate forms connect the widely differing sub-genera of 
Podocarpus with one another, but on a study of their reproductive structures 
alone it is impossible to determine definitely which group of species is the 
most primitive. Eupodocarpus , on the whole, may be so considered, for in 
the structure of its male and female gametophytes it resembles the Abietineae 
more closely than do any of the others. The poor development of spongy 
tissue and the small number of archegonia in Stachycarpus , with the almost 
complete freedom of the nucellus in one of its species, shows that this sub- 
genus has progressed considerably from the primitive abietineous condition. 
Dacrycarpus , with its fused bract and three-winged pollen, is obviously the 
most specialized member of the sub-genera. 
A rather close series unites the parent genus with Dacrydium through 
D. Bidzvillii , for this species, although it possesses the typical subulate 
leaves of its genus, has nearly the strobilar structure of Eupodocarpus , save 
that its nucellus, integument, and epimatium have all attained complete 
freedom from one another. Dacrydium proper has progressed much further, 
and only during a very young condition of the cone, when the epimatium, 
bearing an apical knob, completely surrounds the ovule, is the resemblance 
to Podocarpus at all marked. The female gametophyte of Dacrydium by 
the decrease in number and increase in size of its archegonia shows clearly 
a more advanced condition than does that of Eupodocarpus . 
In Podocarpus dacrydioides the three-winged pollen-grain and the com- 
