40 On the Formation of a Local Museum.
The Mineral department may be arranged according to
the successive strata, or layers, of which the soil consists.
The several kinds of peat, sand, gravel, clay, &c, may be
preserved in glass jars, and the various fossils which may be
from time to time discovered should be arranged according to
their position in the scale of animated beings.
The Vegetable department may have two leading divisions,
the first comprising the non-flowering plants, as Lichens,
Fungi, Mosses, and Ferns, sometimes called Acotyledons
(without cotyledons or seed-leaves), or Cryptogams (concealed
fructification, or seedless), because they do not bear manifest
flowers, nor produce seeds containing an embryo, as do the
great classes of Dicotyledons and Monocotyledons.
The second division comprises the flowering plants, and
may have two leading subdivisions, illustrative of the two
great classes into which flowering plants are to be found
grouped in nature.
These subdivisions are named, according to the manner in
which the wood is formed, Exogens and Endogens.
Exogens (producing outwards), so called from the new wood
being formed in rings placed outside the old, are also called
Dicotyledons, from the seed having two rudimentary leaves ;
the plants in their early condition, while yet enclosed in the
seed, nearly always having two (sometimes more) small
opposed lobes or leaflets. In this subdivision the parts of
the flowers are most frequently in fives or fours, and the small
veins of the leaves are usually irregularly netted, as e.g. in
the oak and the beech.
Endogens (producing inwards), so called because the plants,
having woody stems, form bundles of wood which do not
usually increase in thickness year by year; once formed,
they remain unaltered in diameter, scattered through the
pith-like substance of the stem. In this class (also called
Monocotyledons from the seed having only one rudimentary
leaf) the parts of the flowers are usually in threes, and the
veins of the leaves, excepting in a few orders, are parallel, or
if diverging are not irregularly netted, as e.g. in wheat,
grass, reeds, and rushes.