162
THE ESSEX NATURALIST.
Araucaria as a simple case; its great cone consists of a large
number of spirally arranged bracts or carpels, differing little
from the foliage-leaves, and each bract bears a large ovule closely
adhering to its upper surface. As Prof. Seward points out,
the arrangement recalls that seen in Lycopodium or Club Moss
in which the fertile leaves also bear sporangia on their upper
surface.
In the large group to which the Pines belong, the bracts
of the female cone are quite unlike the needle-like foliage leaves,
and more nearly resemble the bud-scales, which, however, are
only modified leaves. They are small and have at their base
on the upper surface a large scale bearing two ovules. In a
young cone the bracts can easily be seen; but in a mature cone
the ovule-bearing scales have grown to be so much larger and
stouter that it is only by pulling the cone to pieces that the
minute stunted bracts can be made out. Cedars, larches, spruces,
and silver-firs all have cones, of much the same type, and spirally
arranged leaves.
In the giant Sequoias, and the Deciduous-Cypress, Taxodium,
the ovuliferous scale is inconspicuous and closely united with the
bract. In the cypresses, Arbor-Vities and junipers, no ovuli-
ferous scale is present in the female cone, and the bracts and also
the leaves are either opposite or arranged in whorls.
The yew is the only representatie commonly grown in gar-
dens of the large family of conifers, the Taxaceae, in which cone-
formation is imperfect in the female flower, with the carpels
reduced to few, or, in yew, to one, and bearing only one or two
ovules. When ripe the seed is usually more or less enveloped
by a fleshy outer coat, familiar in the sweet-tasting rosy cup of
the yew berry.
In habit the conifers are Xerophytes, that is, they are adapted
to dry ground. In warm regions they thrive best in light sandy
soils. In cold climates the ground in winter is physiologically
dry, since the roots are unable to absorb very cold water. To
guard against undue evaporation, the leaves have a comparatively
small surface, the epidermis covering them is strongly cuticu-
larized, and the stomata are often deeply sunk. It is possible
that no true leaf-blades are formed either in conifers or even in
Ginkgo, and that what we see is a leaf-stalk doing duty for a leaf,
as is probably the case also in Monocotyledons.