The plants belonging to this order have so strong a family likeness to each other as to be easily recognised; and they are all distinguished botanically by the swollen joints of their stems, and their opposite undivided leaves, which are generally connate, that is united, and sheathing the stem. The order is divided into two sections, viz.: Sileneæ, in which the sepals are united into a tube, and which section includes the genera Silene, Dianthus, Saponaria, Lychnis, and Agrostemma; and Alsineæ, in which the sepals are either quite distinct, or only slightly cohering at the base, and which includes Stellaria, Arenaria, Cerastium, Spergula, and several other British weeds. The Chickweed was called by Linnæus _Alsine media_, but the genus Alsine is now united to Stellaria. [Illustration: FIG. 118.—THE CARNATION.] The Wild or Clove Carnation (_Dianthus Caryophyllus_), which may be considered the type of the order, has an erect stem, swollen at the joints, with connate leaves, (see _a_ in _fig._ 118). The flower, when single, consists of five petals, each with a very long narrow claw (_b_), and a rather broad limb or blade (_c_) serrated at the edge. The calyx (_f_) is tubular, with five vandyked teeth, which are in fact the tips of five sepals, into which the tube of the calyx may be easily divided with a pin. The tubular form of the calyx is admirably contrived to support the long claws of the petals, and to keep them in their proper places; particularly when the flowers are double, as the weight of the petals in that case frequently bursts the tube of the calyx. Every one fond of pinks and carnations must have observed the miserable appearance of the flower when thus deprived of its natural support; and to prevent the premature destruction of prize-flowers by this misfortune, professed florists sometimes slip a curiously-cut piece of card-board over the bud, which remains on after the expansion of the flower, and prevents the petals from falling out of place. Some florists tie the calyx round with thread, instead of using a pasteboard ring, which answers the same purpose. At the base of the calyx are two, four, or six leafy appendages (_g_), resembling bracts, which are called the calycine scales. These imbricated scales are, however, only found in the genus Dianthus. There are ten stamens (_d_) unequal in height, but none of them longer than the ovary round which they are placed. The ovary and the stamens are concealed in the cup of the flower, but the former is furnished with two styles, terminating in two long stigmas (_e_), which project beyond the flower, and which, when magnified, appear delicately fringed.