8 BOTANICAL GAZETTE [yULY 
resinous character of the ray-cells. This feature may also be well 
seen in P. palusiris, already referred to. The contrast in the con- 
tents of the ray-cells as they occur in the wood of the cone or of a 
vegetative branch is very strongly marked. 
It may be inferred that we have overlooked the presence of 
tracheary marginal cells in the Cretaceous Pityoxyla, which are 
the subject of the present article. This view cannot however be 
accepted, as the wood of some of our partially charred specimens 
is in a perfect condition of preservation, often not even showing 
the spiral striations which are generally found as a feature of deca 
in many fossil woods, otherwise well preserved. Moreover, in 
shallow rays consisting of a single stratum of cells, which in the 
case of modern species of Pinus are composed entirely of tracheids, 
the cells are parenchymatous and invariably filled with a dark brown 
resinous content, which leaves no doubt as to their histological 
nature. The cells on the margins of the rays in our Pityoxylon 
are moreover related to the central cells of the rays and to each © 
other by simple pits and not by bordered pits, as is the case with 
the marginal tracheids. It is obvious that the ray-structure of 
Pinus underwent a great change in the passage from the Mesozoic 
to the Tertiary period. 
On account of the geographical occurrence of the Pityoxylon, 
which has just been described, it is called Pityoxylon statenense. 
The diagnosis is as follows: 
Transverse —Annual rings narrow, sometimes not clearly marked; wood _ 
parenchyma absent except in the periphery of the resin canals, which may occur ~ 
in any part of the annual rings and are often stopped with tyloses; rays highly 
resinous; bordered pits present on the tangential walls of the autumnal tracheids; : 
tracheids about 25 « in diameter. 
Radial.—Radial pits of tracheids about 17 u in diameter, in a single vertical 
row, round with a round mouth; pits of the ray-cells about one per tracheid, 
round or somewhat elliptical, ro # in diameter; ray-cells all parenchymatous, 
very resinous, length from 100 to 120 #; marginal ray tracheids quite absent. 
Tangential—Rays of two kinds, linear and fusiform, the latter containing 
resin canals which are surrounded with rather thick-walled parenchyma; resin 
canals often occluded by tyloses; tangential pits present in the autumn wood. 
In addition to the Pityoxylon described above, we have examined 
another of the same type, which was secured by Dr, Isaac BowMAN. 3 
