[PENHALLow] NORTH AMERICAN SPECIES OF DADOXYLON 73 
In a radially longitudinal section, the inner bark consists of verti- 
cally elongated parenchyma elements, and it is penetrated throughout 
by narrow resin cells which accumulate on its outer face, become in- 
dividually broader and form a zone 2-3 layers thick (figs. 5 and 6). 
The resin canals appear to be devoid of transverse septa, and are always 
full of resinous matter in a more or less granular form. 
In the middle bark the parenchyma elements are radially elongated 
as in the transverse section, and the structure is penetrated by numerous 
resin canals which traverse the tissue in a direction chiefly coinciding 
with the axis of growth, but as they branch, they often become trans- 
verse or partially so. (Fig. 7.) 
Transverse—Tracheids very variable, growth rings obscure. 
Radial.—Structure of the medullary rays not determinable. 
Bordered pits hexagonal, in two rows throughout. 
Tangential—Rays numerous and variable, 31-57 mic. broad; the cells very 
variable in form and size, thin walled, often broader than high, 
chiefly 1-seriate, often more or less 2-seriate. 
CORDAITES PENNSYLVANICUM, Dn., n. sp. 
An unrecorded species collected by Dr. Newberry from the Car- 
beniferous at Pittsville, Pa. 
Transverse.—Tracheids 44 x 44 mic. broad, the walls 6.7 mic. thick. Growth 
rings present, the summer wood about 8 tracheids thick, the 
tracheids about 12.5 mic. radially, the walls 3.1 mic. thick. Resin 
passages and resin cells wanting. 
Radial.—Ray cells all of one kind, conspicuously but gradually narrower 
toward the ends, equal to about 3 tracheids ; the lateral walls with 
round or oval pits, about 2-3 per tracheid. 
Tangential—Rays medium, broad, the cells round or transversely oval, vari- 
able, 25-31 mic. broad. 
CoRDAITES RECENTIUM, Dn., n. sp. 
An undescribed species from the Permian or Permo-Carboniferous 
of Prince Edward Island. This was regarded by Sir William Dawson 
as being closely related to C. materiarium, if not identical with it. The 
characters, however, are such as to mark it off as a distinct species. 
Transverse.—Tracheids 47 x 53 mic. broad, the walls much reduced by decay. 
Radial.—Ray cells all of one kind, about equal to 2 tracheids; the lateral 
walls with round pits about 1 (?) per tracheid; the cells conspicuously 
narrower at the ends. 
