plains of Barbary, of which it is a native; and even in this country it may be made to assume the character of a small tree, by keeping it during winter in a hothouse or greenhouse. I was very much surprised to find that Mignonette has been introduced barely a century; and it seems difficult to imagine how those of our ancestors who were fond of flower-gardens contrived to do without it. I have only to add that there are several species of Reseda, one of which (_R. luteola_) is a British plant used in dyeing, and is called Dyer’s Weed, or Weld. ORDER XV.—DATISCEÆ. There is only one genus of three species, which are coarse hardy perennials, having the appearance of hemp; and only grown in England in botanic gardens. ORDER XVI.—CAPPARIDEÆ.—THE CAPER TRIBE. This order is divided into two sections, viz., the true Capers, and the Cleomes; both of which have very long and conspicuous stamens. The common Caper (_Capparis spinosa_) has a large and handsome flower, with a distinct calyx and corolla, both in four parts. The petals are white, and so delicate in their texture as to fade in a few hours if exposed to the sun; and the stamens, which are very numerous, have rich purple filaments. In the centre is the pistil, with a very long stalk, and the ovary at the point, instead of at the base, with no style, and a very small stigma. In consequence of this curious construction, the seed-pod, which is fleshy, and hangs downwards, appears to be on a much longer stalk than the flower. The shrub is spiny, and in its natural habitat it grows among stones and rocks. It is the unopened flower-buds that are pickled. The genus Cleome consists principally of annuals, with very handsome flowers, which have very long stamens, and a pistil of the same construction as in Capparis, but the fruit is a dry capsule. The anthers of the stamens are often enfolded in the flowers before they are fully expanded, so that the filaments appear bent, till at last they open fully and hang down. There are a few other genera in the order, but they are little known in England. ORDER XVII.—FLACOURTIANEÆ. The plants belonging to this order are mostly Indian plants, little known in Europe. ORDER XVIII.—BIXINEÆ.—THE ARNOTTA TRIBE. _Bixa Orellana_ is a shrub, a native of South America, which requires a bark stove in England. It has pink flowers with five petals, and a green calyx of as many sepals. The stamens are numerous; but they are on rather short filaments. The leaves are very large and heart-shaped. The fruit is a berry, and the pulp in which the seeds are immersed, when dry, is the Arnotta used in colouring cheese. ORDER XIX.—CISTINEÆ.—THE CISTUS TRIBE. There are only four genera in this order, viz., Cistus, Helianthemum, Hudsonia, and Lechea; and though there are almost innumerable plants comprised in it, they nearly all belong to the first two.