Annual, biennial, or perennial herbs, usually erect and glabrous. Leaves simple, entire, opposite or whorled (except in Menyanthes, where they are alternate and trifoliolate; and alternate and floating in Limnanthemum), exstipulate, often strongly nerved. Flowers regular, bisexual, solitary or in dichotomous or trichotomous cymes. Calyx inferior, 4- to 8-lobed; lobes valvate or contorted in bud. Corolla hypogynous, often persistent, rotate, funnel-shaped or campanulate, 4- to 8-lobed; lobes mostly contorted in bud. Stamens 4 to 8, inserted upon the corolla-tube; filaments free. Capsule 1- or partially 2-celled, containing many seeds attached to 2 opposite parietal placentas. Seeds small, albuminous. This order numbers about 60 genera and 450 species, chiefly from temperate and mountainous regions. Several of our native species are very beautiful, and a few of them merit introduction into large gardens. The Bog-Bean, Menyanthes trifoliata, is a hand-some plant for marshy bogs. It has trifoliate leaves and radical scapes of white or pink fringed flowers about a foot high. Limnanthemum nymphaeoldes is a rare aquatic plant with small orbicular floating leaves and bright yellow umbellate flowers about 1 inch in diameter. The Yellow Wort, Chlora perfoliata, is a glaucous annual growing a foot or more high, remarkable on account of the leaves being joined together or connate by their bases. The bright yellow flowers are borne in trichotomous cymes. There is a fine variety in cultivation with flowers about an inch in diameter called gran-difldra. Besides the above we may mention the Centaury, Erythraea Centaurium, a pretty annual with small pink or white flowers; and Gentiana Pneumonanthe, a perennial species from 1 to 2 feet high, bearing large deep blue flowers towards the end of Summer.