en these
three points are apophyses of irregular pentagonal or hexagonal outline,
with three scales only in mutual contact (figs. 63, 64). Such are the
majority of the scales of the cone and represent more or less indefinite
conditions of phyllotaxis.

The cones of Hard Pines, by reason of relatively more and smaller scales
and of a more conical form, attain a higher phyllotaxis and a more
complex condition, two or even three orders being represented on a
single cone; while the cones of Soft Pines, by reason of relatively
fewer and larger scales and a more cylindrical form, are of lower
phyllotaxis, with one order only more or less definitely presented.
Therefore phyllotaxis furnishes another distinction between the two
sections of the genus, but its further employment is exceedingly
restricted on account of the constant repetition of the same orders
among the species.

[Illustration: PLATE V. PHYLLOTAXIS OF THE CONE]

THE CONE-TISSUES. Plate VI.

The axis of the cone is a woody shell, enclosing a wide pith and covered
by a thick cortex traversed by resin-ducts. By removing the scales and
cortex from the axis (fig. 65) the wood is seen to be in sinuous strands
uniting above and below fusiform openings, the points of insertion of
the cone-scales. From the wood, at each insertion, three stout strands
enter the scale, dividing and subdividing into smaller tapering
strands whose delicate tips converge toward the umbo. Fig. 70 represents
a magnified cross-section of half the cone-scale of P. Greggii; at (a)
is a compact dorsal plate of bast cells; at (e) is a ventral plate of
the same tissue but of less amount; at (b) is the softer brown tissue
enclosing the wood-strands (d, d) (the last much more magnified in fig.
69) and the resin-ducts (e, e).

WOOD STRANDS.

The wood-strands, forming the axis of the cone, differ in tenacity in
the two sections of the genus. Those of the Soft Pines are easily pulled
apart by the fingers, those of the Hard Pines are tougher in various
degrees and cannot be torn apart without the aid of a tool. This
difference is correlated with differences in other tissues, all of them
combining in a gradual change from a cone of soft yielding texture to
one of great hardness and durability.

If a cone scale of P. ayacahuite is stripped of its brown and bast
tissues (fig. 66) and is immersed in water and subsequently dried, there
is at first a flexion toward the cone-axis (fig. 67) and then aw