CRETACEOUS CONIFERALES 73 
with that found in certain Cordaitales. If the occurrence of resin 
canals as a result of wounding in the wood of those more modern 
Abietineae (Cedrus, Abies, Tsuga, Pseudolarix), which are normally 
without resin canals in the secondary wood, is to be regarded as a 
reversionary phenomenon, as it apparently must be, in view of all 
the evidence now at our disposal, it involves no distortion of logical 
principles to regard the traumatic resin canals of Brachyoxylon and 
Araucariopitys as likewise reversionary features. Since the posses- 
sion of ligneous resin canals is a very ancient characteristic of the 
Abietineae, recorded by Goeppert as far back as the Carboniferous 
of Waldenburg, it is highly probable, on the basis of the evidence 
of traumatic resin canals, that Ше Brachyoxylon and Jraucariopitys 
types of wood are as truly derived from that of the older Abietineae 
as is the Cedroxylon type of Kraus found in the more modern Abie- 
tineae (Cedrus, Abies, Tsuga, etc.). It may accordingly be con- 
sidered as highly probable that the Araucarineae possessed of the 
Brachyoxylon and Araucariopitys type of wood are more or less 
closely related in their origin to the ancestral stock of the Abietineae. 
Further, the free ovuliferous scales found in the female cone of 
the Abietineae corresponds according to the weight of evidence in a 
general way to a reduced branch, axillary to the subtending so-called 
sterile bracts. In the Araucarineae, as is specially well shown in 
some of the fossil species described structurally in this Memoir, we 
have instead of the two separate scales a complex organ made up, if 
we may judge from the double nature of the persisting fibrovascular 
structures, of two scales, ovuliferous and sterile, such as are found in 
the Abietineae, congenitally fused together. If the fusion of ovulif- 
erous and sterile scales be admitted for the Araucarineae, and it can 
scarcely be denied in view of the strong degree of approximation of 
the wood structure of the older Araucarineae to that of the Abie- 
tineae, as described in this Memoir and exemplified by the Brachy- 
oxylon and Araucariopitys types of wood, it follows that the tribe 
of conifers which presents the ovuliferous scale in the free condition, 
viz., the Abietineae, is the older. 
But the strongest evidence in favor of the correctness of our 
view is furnished by the leaf structure of Cretaceous pines, which 
present a more archaic type of foliar bundle than is found in those 
species of Pinus now living. In the genus Prepinus the archaic 
characters of the leaf-bundle are most strongly marked of all, for 
