989. The names of the classes and orders of the Natural System have long been in a very unsettled state, almost every botanist who has written upon that system having suggested different names for the orders and classes, and a different mode of arranging them. The following is a sketch of some of the principal modes that have been adopted, abridged from Dr. Lindley's Vegetable Kingdom: - Ray, who first broached the idea of a Natural System, arranged his plants into those with flowers, and those without; and those with flowers he divided into Dicotyledons and Monocotyledons, from the number of their seed leaves. His orders were nearly the same as those of Jussieu. Linnï¾µus left only the fragments of a Natural System. In it there were no classes, but nearly seventy orders, which were named in a most irregular manner, sometimes from the names, and sometimes from the peculiarities of the plants contained in them. Jussieu had three principal classes, which he named from the number of their cotyledons, and which were divided into sub-classes and tribes ; the first named from the number of their petals, and the second from the position of their stamens, and corolla, and the form of their anthers. The orders he named generally from the principal genus contained in each ; sometimes merely changing the name of the genus into plural, according to the usual rules of the Latin language; and sometimes changing the last syllable into aceï¾µ. In some few cases, the orders were not named from the genera, but from the peculiarities of the plants contained in them, such as Labiatï¾µ, Umbelliferï¾µ, Leguminosï¾µ, Cruciferï¾µ, &c. De Candolle, in his Theorie E'lementaire de la Botanique, divides plants into two great classes, from their physiological construction. These were again divided and named, first, from the number of their cotyledons, and their mode of forming-wood ; and, secondly, from the number and position of their petals. These sub-classes were again divided into cohorts, or alliances, principally from the construction of the seed-vessels. Most of the orders were named by adding ceï¾µ to the name of the principal genus in each order, as Rosaceï¾µ, from Rosa ; or by changing the last syllable into cï¾µ, as Rhamneï¾µ, from Rhamnus, Menispermeï¾µ, from Menispermum, &c. The names of Leguminosï¾µ, Cruciferï¾µ, &c., were retained. It is this arrangement which is now generally understood when speaking of the Natural System ; and on this account it will hereafter be given more in detail. Agardh, in 1825, published a small work called Classes Plantarum, the object of which was to group the natural orders into a kind of classes, equivalent to what were afterwards called alliances ; and in 1830, Professor Bartling published a work of a similar nature, though without making any allusion to that of Bishop Agardh. Dr. Lindley, in the first edition of his Introduction to the Natural System of Botany, published in 1830, proposed a slight modification of De Candolle's plan, by which the arrangement of the orders was somewhat changed, Umbelliferï¾µ being placed first instead of Ranunculaceï¾µ, &c. In 1833, Dr. Lindley published his Nixus Plantarum, which, he says, 'was an attempt, in imitation of Agardh and Bartling, to reduce the Natural Orders into groups subordinate to the higher divisions. Such groups were called Nixus (tendencies). The author threw aside the distinctions between perigynous and hypogynous insertion, as uncertain and leading to bad grouping ; insisted upon the value of albumen as a primary character; and objected to the general principle that the sections of plants are to furnish their character, and not a character the section.' (Lindley's Vegetable Kingdom, Introduction, p. xli.) In 1836, Dr. Lindley published a second edition of his Natural System of Botany, the arrangement adopted in which was nearly the same as that proposed in the Nixus Plantarum. 'An attempt was also made to reform the nomenclature of the Natural System, by making all the names of divisions of the same value end in the same way. The orders were distinguished by ending in acï¾µ, the sub-orders in cï¾µ, the alliances in ales, and certain combinations called groups in osï¾µ.' (Ibid. p. xlvi.) In 1838, in an article entitled Ezogens, in the Penny Cyclopï¾µdia, Dr. Lindley proposed a new arrangement based chiefly on the quantity of albumen in the seeds; and dividing the Exogenous plants into five classes, depending on the formation of the flowers. In 1839, in the miscellaneous matter of the Botanical Register, Dr. Lindley published an improvement of this plan, by which the number of primary classes was increased to eight; and in 1846, he published his latest and most perfect plan, on which his great work entitled The Vegetable Kingdom is arranged. According to this plan, plants are divided into the asexual or flowerless, and the sexual or flowering ; and subdivided into seven classes, each class containing several alliances or groups, and each group several orders. In all there are fifty-six groups or alliances, and 303 orders.