cies are regarded as permanent and essentially unchanged
in their succession of individuals through the actual ages.

527. There are, at nearly the lowest computation, as many as one hundred
thousand species of phanerogamous plants, and the cryptogamous species
are thought to be still more numerous. They are all connected by
resemblances or relationships, near and remote, which show that they are
all parts of one system, realizations in nature, as we may affirm, of
the conception of One Mind. As we survey them, they do not form a single
and connected chain, stretching from the lowest to the highest organized
species, although there obviously are lower and higher grades. But the
species throughout group themselves, as it were, into clusters or
constellations, and these into still more comprehensive clusters, and so
on, with gaps between. It is this clustering which is the ground of the
recognition of _kinds_ of species, that is, of groups of species of
successive grades or degree of generality; such as that of similar
species into _Genera_, of genera into _Families_ or _Orders_, of orders
into _Classes_. In classification the sequence, proceeding from higher
or more general to lower or special, is always CLASS, ORDER, GENUS,
SPECIES, VARIETY (if need be).

528. =Genera= (in the singular, _Genus_) are assemblages of closely
related species, in which the essential parts are all constructed on the
same particular type or plan. White Oak, Red Oak, Scarlet Oak, Live Oak,
etc., are so many species of the Oak genus (Latin, _Quercus_). The
Chestnuts compose another genus; the Beeches another. The Apple, Pear,
and Crab are species of one genus, the Quince represents another, the
various species of Hawthorn a third. In the animal kingdom the common
cat, the wild-cat, the panther, the tiger, the leopard, and the lion are
species of the cat kind or genus; while the dog, the jackal, the
different species of wolf, and the foxes, compose another genus. Some
genera are represented by a vast number of species, others by few, very
many by only one known species. For the genus may be as perfectly
represented in one species as in several, although, if this were the
case throughout, genera and species would of course be identical. The
Beech genus and the Chestnut genus would be just as distinct from the
Oak genus even if but one Beech and Chestnut were known; as indeed was
once the case.

529. =Orders= are groups of genera that resemble ea