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MR. W. RUSHTON : STRUCTURE OF THE 
The amount of summer wood per annual ring in each species is highest in 
J. recurva and J. communis, where it sometimes occupies almost half of each 
ring, or may be reduced to the last 4—8 rows of tracheids up to the outer 
limit of the ring, whereas in J. Wallichiana and J. macropoda it rarely 
occupies more than 2-6 rows from the outer limit of the year’s growth. 
The tracheids are arranged in straight radial rows, square to round in 
outline in transverse sections in the spring wood, and oblong in the summer 
wood with the long axis tangential, and show а length of 0'5—3 mm. in 
all species. Bordered pits occur on the radial walls of both spring and 
summer tracheids, arranged in a single longitudinal row with occasional 
pairs in the spring wood, and wholly uniseriate in the summer wood. On 
the tangential walls of the latter the bordered pits occur somewhat sporadi- 
eally, but only occasionally on the tangential walls of the spring wood, 
especially towards their ends, in cases where the tracheids happen to bend 
or twist about radially. The number of pits per tracheid varies in the 
different species, being largest in J. macropoda, where they are more or less 
contiguous, and least numerous in J. communis, where they are more distant. 
In J. Wallichiana and J. recurva intermediate conditions were found with 
numbers in between. The ends of the tracheids are more or Jess rounded off 
except where they happen to end near a medullary ray, in which case they 
are frequently bent out of their course and run along the upper or lower 
surface of the ray-cells radially (Pl. 1. fig. 1), or where two tracheids come 
together, one from above and one from below, when they are much contorted 
with the common ends flattened. When this flattening is well marked a 
bordered pit is invariably present on the common wall (fig. 2). 
This bending of the tracheids is of frequent occurrence in all the Indian 
species, more especially in J. recurva and J. macropoda. 
Lignified bars (Sanio’s bars) are numerous in all the species, in some cases 
running radially throughout the whole width of an annual ring (figs. 3, 4, 5). 
The bars readily stain with lignin stains such аз phloroglucin and hydrochloric 
acid, ete., whilst above and below the pit-areas the clear unlignified rims 
(Sanio’s rims) so common in pine-wood can be demonstrated, but they are 
not so numerous or as clear to see as in many of the Pine species. 
Professor Groom and myself, working on the East Indian Pines (Journ. 
Linn. Soc., Bot. xli.), found these unlignified areas to be of a pectic nature, 
and not cellulose as previously stated by Miss Gerry (Ann. Bot. 1910), so 
that it was thought worth while to investigate their nature in Juniperus so 
as to find out whether they are cellulose or pectin. 
To work out this point, radial and tangential sections were taken of all 
four species and all submitted to similar treatment, one set of solutions being 
used throughout. The colourless rims (Sanio’s rims) occur in all four 
species, but in different proportions according to the number of pits per 
tracheid and their distance apart. 
