534 
Butt. — Pityostrobus macrocephalus , L. and H. 
a considerable amount of resemblance to the Araucarineae. Instead of 
opposite pitting, pitting in the cone-axis and early wood of the Abietineae 
has characteristically either scattered uniseriate pits or biseriate ones which 
are alternately arranged. Sometimes even the pits are flattened by mutual 
contact.’ The pore of the bordered pit is usually circular, but sometimes 
elongated and oblique. In the latter case ‘ crossing ’ of the pores of super- 
posed bordered pits on opposite walls of the tracheides was often observed. 
In a very few instances faint white lines were observed between the 
bordered pits, but for the most part no evidence of the presence of rims of 
Sanio could be detected. 
A remarkable feature is the entire absence of resin-parenchyma or of 
resin-canals. This is confirmed 
by the examination of transverse 
sections. On the other hand, 
what are probably resin plates or 
‘ spools ’ are of common occur- 
rence in many of the tracheides. 
It is interesting to notice that 
Thomson finds resin tracheides 
to be present in the cone-axes of 
species of Pinus , and he regards 
this as a retention of the primitive 
condition which is found in the 
Araucarineae and Cordaitales. 
Trabeculae, or incomplete 
septations of the tracheides, 
Text-fig. i. P. ovatiis. Radial longitudinal . i 1 
section of wood from base of cone, showing resin- OCCUT in Several places. 1 Hey 
spools, bordered pits, and walls of medullary ray cells. may, sometimes, be difficult to 
Cowderoy Collection, V 11003 c. Diagram from a . 
photograph. distinguish from the walls of the 
medullary ray cells, but are 
usually thicker and better preserved. The medullary rays are not well 
preserved. They are usually several cells in height, but always uniseriate. 
In almost all cases, and large numbers are to be found in the radial 
sections from the Sedgwick Museum cone, the course of the medullary 
rays is markedly oblique to that of the tracheides. Owing to the poor 
state of preservation and to the thickness of the sections, the details 
of pitting are only observable with difficulty ; where clearly seen the 
walls exhibit some indications of ‘ Abietinean pitting ’. No definite ray 
tracheides were noted, but sometimes the shape of the marginal cells of the 
ray is suggestive in this connexion. The tracheide field is occupied by 1-2 
large ‘ Eiporen ’ ; these pits are most conspicuous in transverse sections of 
the cone-axis. The cambium and phloem, which are not always preserved, 
are composed of rather crushed, thin-walled cells filled with carbonaceous 
