Sect. VI.—Nomenclature.
19. The Nomenclature of any branch of Natural History is the collection of names of all its species; which, when they become extremely numerous, requires some artifice to make it possible to recollect or apply them. The known species of plants, for example, were 10,000 at the time of Linnæus, and are now probably 60,000. It would be useless to endeavour to frame and employ separate names for each of these species.
The division of the objects into a subordinated system of classification enables us to introduce a Nomenclature which does not require this enormous number of names. The artifice employed to avoid this inconvenience is to name a Species by means of two (or it might be more) steps of the successive division. Thus in Botany, each of the genera has its name, and the species are marked by the addition of some epithet to the name of the genus. In this manner about 1,700 generic names, with a moderate number of specific names, were found by Linnæus sufficient to designate with precision all the species of vegetables known at his time. And this Binary Method of Nomenclature has been found so convenient that it has been universally adopted in every other department of the Natural History of organized beings.
Many other modes of Nomenclature have been tried, but no other has at all taken root. Linnæus himself [134] appears at first to have intended marking each species by the Generic Name accompanied by a characteristic Descriptive Phrase; and to have proposed the employment of a trivial Specific Name, as he termed it, only as a method of occasional convenience. The use of these trivial names, has, however, become universal, as we have said, and is by many persons considered the greatest improvement introduced at the Linnæan reform.
Both Linnæus and other writers (as Adanson) have given many maxims with a view of regulating the selection of generic and specific names. The maxims of Linnæus were intended as much as possible to exclude barbarism and confusion, and have, upon the whole, been generally adopted; though many of them were objected to by his contemporaries (Adanson and others[35]), as capricious or unnecessary innovations. Many of the names, introduced by Linnæus, certainly appear fanciful enough: thus he gives the name of Bauhinia to a plant with leaves in pairs, because the Bauhins were a pair of brothers; Banisteria is the name of a climbing plant, in honour of Banister, who travelled among mountains. But such names, once established by adequate authority, lose all their inconvenience, and easily become permanent; and hence the reasonableness of the Linnæan rule[36], that as such a perpetuation of the names of persons by the names of plants is the only honour botanists have to bestow, it ought to be used with care and caution.
[35] Pp. cxxix. clxxii.
[36] Phil Bot. s. 239.
The generic name must, as Linnæus says, be fixed[37] before we attempt to form a specific name; ‘the latter without the former is like the clapper without the bell.’ The name of the genus being established, the species may be marked by adding to it ‘a single word taken at will from any quarter;’ that is, not involving a description or any essential property of the plant, but a casual or arbitrary appellation[38]. Thus the [135] various species of Hieracium[39] are Hieracium Alpinum, H. Halleri, H. Pilosella, H. dubium, H. murorum, &c. where we see how different may be the kind of origin of the words.
[37] Ib. s. 222.
[38] Ib. s. 260.