THE nomenclature of Botany as rescued from confusion by Linnæus, has in modern times been in some danger of relapsing into disorder or becoming intolerably extensive, in consequence of the multiplication of genera by the separation of one old genus into several new ones, and the like subdivisions of the higher groups, as subclasses and classes. This inconvenience, and the origin of it, have been so well pointed out by Mr. G. Bentham[65\4], that I shall venture to adopt his judgment as an Aphorism, and give his reasons for it. [Note 65\4: _Linnæan Society's Proceedings_, vol. ii. p. 30 (June, 1857).] APHORISM XXIII. _It is of the greatest importance that the Groups which give their substantive names to every included species should remain large._ IT will be recollected that according to the Linnæan nomenclature, the genus is marked by a substantive, (as _Rosa_), and the species designated by an adjective added to this substantive, (as _Rosa Alpina_); while the natural orders are described by adjectives taken substantively, (as _Rosaceæ_), But this rule, though it has been universally assented to in theory, has often been deviated from in practice. The number of known species having much increased, and the language of Linnæus and the principles of Jussieu having much augmented the facilities for the study of affinities, botanists have become aware that the species of a genus and the genera of an order can be collected into intermediate groups {347} as natural and as well defined as the genera and orders themselves, and names are required for these subordinate groups as much as for the genera and orders. Now two courses have been followed in providing names for these subordinate groups. 1. The original genera (considering the case of genera in the first place) have been preserved, (if well founded); and the lower groups have been called _subgenera_, _sections_, _subsections_, _divisions_, &c.: and the original names of the genera have been maintained for the purpose of nomenclature, in order to retain a convenient and stable language. But when these subordinate groups are so well defined and so natural, that except for the convenience of language, they might be made good genera, there are given also to these subordinate groups, substantive or substantively-taken adjective names. When these subordinate groups are less defined or less natural, either no names at all are given, and they are distinguished by figures or signs such as *, **, or § 1, § 2, &c. or there are given them mere adjective names. Or, 2, To regard these intermediate groups between species and the original genera, as so many independent genera; and to give them substantive names, to be used in ordinary botanical nomenclature.