6a ES ad Saal 
A aes aa Se eee ee, ee 
Se ER San ae ee eo ee 
1g1t] JEFFREY—GEINITZIA GRACILLIMA 23 
the pith is the well developed woody cylinder, which is succeeded 
by a zone of well preserved phloem of about a third its diameter. 
External to the phloem lies an irregular and partly destroyed 
cincture, representing the cortex. The magnification is not suffi- 
cient to show that in the cortex there are sclerotic cells similar to 
those found in the pith. 
Fig. 3 shows the structure of the higher part of the cone as 
seen in longitudinal section. Centrally lies the medullary tissue, 
largely occupied by stone cells. Near the region of the wood the 
sclerotic aggregations give place to thin-walled parenchymatous 
elements. The wood is crossed on the right side of the figure, 
which shows it in a good condition of preservation, by shallow 
medullary rays from one to three or four cells in height. The 
rays, as seen in the transverse and the longitudinal radial sections, 
are uniseriate. The broad, so-called fusiform, rays found in the 
pinelike Abietineae are entirely absent. Part of the phloem 
adheres to the surface of the wood on the right, while on the left 
both phloem and cortex are absent. 
Fig. 4 shows a detailed longitudinal section of part of the pith. 
The stone cells, with their layered and laminated walls, can be 
seen intermingled with the thin parenchymatous elements, which 
constitute the rest of the medullary tissues. The lamination of 
the walls of the stone cells is to be regarded as the result of the 
conditions of fossilization, as these cells in similar material from the 
Kreischerville deposits, in the best preserved twigs, show no indica- 
tion of lamination. 
Fig. 5 shows a transverse section of part of the lower region of 
the cone axis. The phloem and xylem are both present and in a 
good condition of preservation. The former occupies the upper . 
part of the figure and is obviously not of the type found in the 
Cupressineae and Taxodineae (Sequoiineae), since the striking 
alternating stripes of hard bast fibers, which are characteristic . 
of the phloem of the two coniferous tribes just mentioned, cannot 
be seen. A zone of decay marks the position of the cambium. 
Below this region appears the wood, composed of rather small 
tracheids. The rays can scarcely be made out, since they are 
composed of smooth thin-walled cells, which very readily collapse. 
