10 MR. W. RUSHTON : STRUCTURE OF THE 
Resin Cells. 
The resin cells in this species always occur close up to the outer limit of 
each annual ring, usually on a level with the last three or four tangential 
rows of the late summer tracheids but never more than the sixth row from 
the outer limit and, oceasionally, on a level with the first two or three rows 
of early spring tracheids. The cells are short and narrow, 65-88 y being an 
average length, with a width of 3-5 p radially and 16 р tangentially, with 
all the walls lignified, the end ones being irregular in outline. 
In this species the resin cells form a more continuous series longitudinally 
than in the others, often 10-20 occurring end to end before they are replaced 
by a wood-tracheid, and often two narrow cells occur side by side, occupying 
only the space of a normal one. On the lateral walls bordered pits are 
common with lenticular openings (fig. 27). 
JUNIPERUS COMMUNIS, Linn. 
This species, although already described, is added for the sake of complete- 
ness, as it occurs in the North- West Himalaya, at 5400—14,000 feet elevation, 
in whieh region it is said to rarely grow to a height of more than 6-7 feet, 
often with a thick stem 18-24 feet in girth. 
Macroscopic (naked eye). 
The wood is very light reddish brown in colour, with 33 rings per inch of 
radius in my specimen, but Gamble gives 35-50 as being general. The rings 
are very variable in width, some being fairly wide and others narrow. The 
medullary rays are just visible. 
Microscopie (tracheids). 
In transverse sections the spring wood gradually merges into the summer, 
but occasionally the transition is more sudden, sometimes the latter occupying 
nearly half the entire ring but in other cases little more than a quarter. 
The length of the tracheidsis shorter in this species than in the others, 
1-2 mm. being an average length, with width of lumen and thickness of wall 
as follows :— 
Width of lumen. Thickness of wall. 
Radial. Tangential. Radial, Tangential. 
Spring wood ......... 18:2 u 8'0 u 19 ш l9. 
Summer wood ...... 3'8 р 3-6 p 28 д 2.8 u 
The ends of the tracheids are more or less rounded off, with occasional 
flattened ones opposed to each other, with a bordered pit between the two. 
Usually, however, the tracheids run straight. The bordered pits on the 
radial walls of the spring and summer wood are arranged in a single row, and 
are not so numerous or so near together as in the other species ; and where 
