32 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 
verse, so that the base of only one of the leaves of the decussate pair 
can be made out. Figure 3, Pl. 28, shows a similar section of the 
same specimen, X 50, in which the upper and lower leaves are those 
best developed in the plane of section. In both of these figures there 
are present abnormal cavities in the substance of the leaves, the exact 
nature of which cannot be made out. Figure 4, Pl. 28, represents 
the central portion of fig. 3, X 100. 
It may be noticed that the elements of the fibrovascular cylinder 
are very immature and somewhat disturbed, as a result of fossiliza- 
tion. It has been found difficult to secure ап old enough twig 
of this species to determine the structure of the secondary wood, 
although the structure of the leaves makes it very probable that we 
have here to do with an araucarineous conifer, since the distribution 
of the transfusion tissue is not lateral to the foliar strands as in 
Thuja and the other Cupressineae, but has the same tendency to 
surround the phloem of the bundle which has been noted in the other 
araucarineous twigs previously described. However we are not left 
entirely to surmise in this case, for in fig. 18, Pl. 8, is shown a young 
twig, X Io, with a single pair of verticillate leaves, which is sufh- 
ciently mature to make it possible to determine the structure of its 
wood as araucarineous. In fig. 4, Pl. 27, is shown a transverse 
section of this fragment, X 35. On the two surfaces of the figure 
may be seen furrows, which mark the line of separation of the two 
leaves. In the center appears the fibrovascular cylinder, in which 
the wood is well developed. Subtending the ends of the woody 
cylinder and opposite clear interruptions in its continuity are the traces 
of the leaves. Figure 5, Pl. 27, represents a transverse section, 
X 35, of the opposite and upper end of the same fragment near the 
level of separation of the tips of the leaves from the surface of the 
stem. On the lower side of this figure one of the leaf traces may 
clearly be seen as a dark spot in the substance of the leaf. At this 
level the traces of the decussate pair of leaves are leaving the central 
cylinder, as may be perceived by noting the corresponding two deep 
opposite bays in the woody cylinder. The central cylinder is sur- 
rounded as a whole by a dark boundary, which appears with par- 
ticular clearness in this figure. ‘The nature of this boundary has not 
been easy to decipher. It is not possible to decide whether it is 
merely a zone of collapsed sieve tubes, such as often occurs in the 
conifers, and which we have found in the case of Brachyphyllum, or 
