I have only to add that each sub-class is divided into numerous orders, which are differently arranged by different botanists; the object being to place those nearest together which are most alike. As no one of these arrangements appears to be decidedly better than the others, I have adopted that given in Mr. Loudon’s _Hortus Britannicus_; marking, where, they occur, the new orders which have been formed, and the alterations in the old ones that have been made since that work was written. CHAPTER I. PHANEROGAMOUS PLANTS—DICOTYLEDONÆ—I. DICHLAMYDEÆ. § I.—THALAMIFLORÆ. In all the plants contained in this chapter the receptacle is a fleshy substance called the thalamus, or disk, which is surrounded by the calyx, and out of which the carpels or seed-vessels, the stamens, and the petals, all grow separately from each other. Sixty-five orders are included in this division, but I shall only describe those which contain plants which have been introduced into Britain, except where the orders chance to contain plants well known in commerce. ORDER I.—RANUNCULACEÆ. The plants belonging to this order are known by their numerous stamens, the anthers of which burst outwardly; by their carpels growing close together without adhering, except in one or two instances; and by the stem-clasping petioles of their leaves, which are generally deeply cut. The flowers when regular have five petals and five sepals, but they differ widely in shape, and the calyx of several of them is coloured so as to resemble a corolla. The seeds are frequently cariopsides; and the plants abound in a watery juice which is acrid, and in most cases poisonous. ORDER II.—DILLENIACEÆ. This order resembles Raminculaceæ in having five petals, five sepals, and numerous stamens; but the anthers burst inwardly instead of outwardly, and there are never more than five carpels, and seldom more than two, which often grow into a berry-like fruit, as in the genus Dillenia from which the order takes its name. One species of this genus is occasionally seen in English hothouses, _Dillenia speciosa_. It has yellow flowers with the five petals apart at the base, and the sepals edged with white. The fruit consists of five carpels growing together with a sort of crown formed by the spreading stigmas. Another genus, some of the species of which are found in British greenhouses, is _Hibbertia_. The species are generally climbing plants, with flowers like those of Dillenia, but smaller, though _H. dentata_ has the petals close together. The difference between the genera consists principally in the carpels, which in Hibbertia are distinct with long filiform styles curving inwards. All the plants contained in this order are evergreen exotic shrubs and trees with simple alternate leaves, and, with only two or three exceptions, the flowers are yellow. ORDER III.—MAGNOLIACEÆ.