The formation of an exact and extensive descriptive language for botany has been executed with a degree of skill and felicity, which, before it was attained, could hardly have been dreamt of as attainable. Every part of a plant has been named; and the form of every part, even the most minute, has had a large assemblage of descriptive terms appropriated to it, by means of which the botanist can convey and receive knowledge of form and structure, as exactly as if each minute part were presented to him vastly magnified. This acquisition was part of the Linnæan Reform, of which we have spoken in the _History_. 'Tournefort,' says De Candolle[50\4], 'appears to have been the first who really perceived the utility of fixing the sense of terms in such a way as always to employ the same word in the same sense, and always to express the same idea by the same word; but it was Linnæus who really created and fixed this botanical language, and this is his fairest claim to glory, for by this fixation of language he has shed clearness and precision over all parts of the science.' [Note 50\4: _Théor. Élém._ p. 327.] {316} It is not necessary here to give any detailed account of the terms of botany. The fundamental ones have been gradually introduced, as the parts of plants were more carefully and minutely examined. Thus the flower was successively distinguished into the _calyx_, the _corolla_, the _stamens_, and the _pistils_: the sections of the corolla were termed _petals_ by Columna; those of the calyx were called _sepals_ by Necker[51\4]. Sometimes terms of greater generality were devised; as _perianth_ to include the calyx and corolla, whether one or both of these were present[52\4]; _pericarp_ for the part inclosing the grain, of whatever kind it be, fruit, nut, pod, &c. And it may easily be imagined that descriptive terms may, by definition and combination, become very numerous and distinct. Thus leaves may be called _pinnatifid_[53\4], _pinnnatipartite_, _pinnatisect_, _pinnatilobate_, _palmatifid_, _palmatipartite_, &c., and each of these words designates different combinations of the modes and extent of the divisions of the leaf with the divisions of its outline. In some cases arbitrary numerical relations are introduced into the definition: thus a leaf is called _bilobate_[54\4] when it is divided into two parts by a notch; but if the notch go to the middle of its length, it is _bifid_; if it go near the base of the leaf, it is _bipartite_; if to the base, it is _bisect_. Thus, too, a pod of a cruciferous plant is a _silica_[55\4] if it be four times as long as it is broad, but if it be shorter than this it is a _silicula_. Such terms being established, the form of the very complex leaf or frond of a fern is exactly conveyed, for example, by the following phrase: 'fronds rigid pinnate, pinnæ recurved subunilateral pinnatifid, the segments linear undivided or bifid spinuloso-serrate[56\4].' [Note 51\4: De Candolle, 329.]