use-tail was established as a
genus under this name by Dillenius; _Caulophyllum_, Michx., that the
Blue Cohosh was published under this name by Michaux. The full reference
in the last-named instance would be, "in Flora Boreali-Americana, first
volume, 205th page,"--in the customary abbreviation, "Michx. Fl. i.
205."

540. =Names of Orders= are given in the plural number, and are commonly
formed by prolonging the name of a genus of the group taken as a
representative of it. For example, the order of which the Buttercup or
Crowfoot genus, _Ranunculus_, is the representative, takes from it the
name of _Ranunculaceae_; meaning _Plantae Ranunculaceae_ when written out
in full, that is, Ranunculaceous Plants. Some old descriptive names of
orders are kept up, such as _Cruciferae_ for the order to which Cress and
Mustard belong, from the cruciform appearance of their expanded corolla,
and _Umbelliferae_, from the flowers being in umbels.

541. =Names of Tribes=, also of suborders, subtribes, and the like, are
plurals of the name of the typical genus, less prolonged, usually in
_eae_, _ineae_, _ideae_, etc. Thus the proper Buttercup tribe is
_Ranunculeae_, of the Clematis tribe, _Clematideae_. While the Rose family
is _Rosaceae_, the special Rose tribe is _Roseae_.

542. =Names of Classes, etc.= For these see the following synopsis of
the actual classification adopted, p. 183.

543. So a plant is named in two words, the generic and the specific
names, to which may be added a third, that of the variety, upon
occasion. The generic name is peculiar: obviously it must not be used
twice over in botany. The specific name must not be used twice over in
the same genus, but is free for any other genus. A _Quercus alba_, or
White Oak, is no hindrance to _Betula alba_, or White Birch; and so of
other names.

544. =Characters and Descriptions.= Plants are _characterized_ by a
terse statement, in botanical terms, of their peculiarities or
distinguishing marks. The character of the order should include nothing
which is common to the whole class it belongs to; that of the genus,
nothing which is common to the order; that of the species nothing which
is shared with all other species of the genus; and so of other
divisions. _Descriptions_ may enter into complete details of the whole
structure.

545. =Terminology=, also called _Glossology_, is nomenclature applied to
organs or parts, and their forms or modifications. Each organ or special