344 Barber,— Cupressinoxy Ion vectense . 
branches and in primary roots the pith is distinct, that of 
lateral roots is point-like if present at all 3 . 
An examination of the ‘ medullary sheath or crown ’ points 
in the same direction. While branch (i) and branch (2) have 
well-marked groups of primary xylem where the tracheides 
lose the radial arrangement (Figs. 5 and 6), roots (1) and (2) 
show rows of tracheides passing directly to the borders of 
the pith (Fig. 7). A search for the primary xylems in 
longitudinal and oblique sections of these specimens has not 
been very successful ; but in the tranverse section of root (i) 
there is a distinct appearance of tracheides with spiral 
thickenings in the pith opposite several of the primary 
medullary rays. 
In the radial sections the appearances are not so con- 
vincing. In branch (1) the tracheides with bordered pits are 
easily seen to be in contact with the spiral ones, these latter 
adjoining the pith-cells. This is what one would expect in 
a section of a shoot. But there is every appearance that 
the same is the case in root (1). The state of preservation in 
root (2) and branch (2) prevents their sections from throwing 
any light on the question. 
The number of primary medullary rays varies in the 
sections. It is not possible to determine them accurately, 
but they seem to be between 2 and 7. 
The cells of the pith in transverse sections are largest in 
the centre, from whence they decrease outwards to the 
‘crown’ of tracheides (Fig. 7). The diameter of the former 
may be taken as about 45 /u, while the outer medullary cells 
measure 10-20 /x. In longitudinal sections the inner cells are 
seen to be flattened transversely, so as to extend across the 
pith, while the cells near the tracheides are elongated in 
the same direction as the latter. 
All the pith-cells are richly pitted. Where undisturbed 
they are circular in transverse section, and have well-marked 
triangular intercellular spaces 5-10-15 /x across. 
1 Nordlinger, Forstbotanik. 
