The plants included in this order have generally the male and female flowers distinct. The calyx is tubular, and generally five-toothed; there are five petals usually connected at the base, and which have strongly marked reticulated veins. There are five stamens, four of which are united so as to form two pairs, with the fifth one free. The anthers are two-celled, and generally very long. There are three or five two-lobed stigmas, which are thick and velvety. The fruit is fleshy, with numerous flat seeds. The leaves are palmate, and very rough; and the plants have succulent stems, and climb by means of their tendrils. The principal genera are, Cucumis, which includes the Melon (_C. melo_), the Cucumber (_C. sativus_), the Mandrake (_C. Dudaim_), the Water Melon (_C. citrullus_), and the Colocynth (_C. colocynthis_); Bryonia, best known by the White Bryony (_B. dioica_); Momordica, including the Balsam Apple (_M. balsamea_), and the Squirting Cucumber (_M. elaterium_); and Cucurbita, including all the kinds of Pumpkin (_C. pepo_), and Vegetable Marrow (_C. ovifera_). To these may be added Lagenaria, the Bottle Gourd; and Trichosanthes, the Snake Gourd, plants far more curious than useful. Some botanists include the Papaw-tree (_Carica Papaya_) in Cucurbitaceæ, but others make it into a separate order under the name of Papayaceæ. ORDER LXXXVI.—PASSIFLOREÆ.—THE PASSION-FLOWER TRIBE. The plants belonging to this order may be instantly recognized by the very singular arrangement of the pistil and stamens. The receptacle is raised in the centre of the flower so as to form a long cylindrical stipe, on which is placed the ovary, with its three styles, each ending in a fleshy stigma; a little lower are five stamens, with their filaments growing together round the stipe, and with large anthers which are attached by the back. At the base of the stipe are two or more rows of filaments without anthers, which are called the rays. There are five petals and five sepals; but some botanists consider the whole to be sepals, and that the petals are wanting. The fruit of some of the species is eatable. It is about the size of a large egg, and contains numerous seeds, which are enveloped in a kind of pulp. ORDER LXXXVI.*—MALESHERBIACEÆ. This order consists entirely of the plants belonging to the genus Malesherbia; which are mostly annuals, or biennials, with very showy blue or white flowers, introduced from Chili in 1832. The genus was formerly included in Passifloraceæ. ORDER LXXXVII.—LOASEÆ.