422 MR. A. C. SEWARD ON A NEW SPECIES OF CONIFER, 
and 11. Between rings 10 and 11 there occur only about 
15 tracheids; between rings 12 and 13 as many as 40 or 
50 tracheids. ; 
The numerous dark patches scattered throughout the section 
represent disorganised groups of woody tissue; it is, however, 
not an easy matter to determine how far some of these are 
due to ordinary decay, or to the agency of some wood-boring 
animal, or to patches of resiniferous cells. There is evidence 
in places of the destructive action of parasitic fungi, but no 
distinct traces have been detected of fungal hyphe. The 
unusually large number of resin canals in certain parts of the 
section, may probably be regarded as an expression of some 
injury sustained by the tree. 
A more detailed examination of the transverse section brings 
to light the following structural features. The tracheids have 
thin and sharply defined walls, with their cavities occupied by 
crystalline material, probably calcite; the thinness of the walls 
is no doubt not an original character, but a pathological 
feature, or the result of partial decay before mineralization. 
The individual tracheids are often found to be more or less 
Separated from one another, as in the summer wood of (PI. II. 
fig.1). As seen in (PI. II. fig. 1), the rings of growth are sharply 
defined. The medullary rays stand out conspicuously by reason 
of the darker coloured contents of the cells, in most cases they 
appear in the transverse section of the stem as single rows of 
radially elongated cells. In the cavities of these ray cells there 
are often found light brown highly refractive granules; these 
may be the remains of cel] contents, but it is difficult, or indeed 
impossible, to determine their exact nature, even under the 
highest magnifying power. In one or two places the elements 
of the medullary rays show faint indications of thin projections 
into the cel] cavity; these may possibly represent the imper- 
fectly preserved ingrowths characteristic of the medullary ray 
tracheids in Pinus, or may be faint indications of a spiral 
Striation on the tracheid walls. Conwentz has figured 
examples of clearly marked striation in tracheids of the Eocene 
Species, Pinus succinifera Conw.,* and less perfect sugges- 
tions of such a striature may be seen in longitudinal sections of 
the present Species of Pinites. 
The resin ducts in some cases have their cavity occupied by 
* ‘Monograph. baltischen Bernsteinbiume,’ 1890, p. 43. pl. 4. fig. 5, 
and pl. 10 fig. 4. 
