Calyx 5-partite. Corolla very deeply 5-lobed, rotate or rotate-campanulate; lobes overlapping to the left and straight or more or less twisted in bud. Corona arising from the staminal-column near or at its base, often membranous, annular, cup-shaped or tubular, toothed or lobed at the top or divided nearly or quite to the base into 5 entire or toothed lobes, with or without a tooth, lobe, thickening or keels within the tube in front of each of the principal teeth or lobes, or on the inner face or at the base of the lobes when the corona is divided. Staminal-column arising at or near the base of the corolla; filament part varying from almost none to a long slender stipe within the corona; anther-appendages membranous or slightly fleshy, inflexed over the apex of the style or connivent or erect around it. Pollen-masses pendulous, solitary in each anther-cell, affixed in pairs by short or long caudicles to the pollen-carriers. Style shorter or longer than the anther-appendages; apical part truncate, conical, or rostrate. Follicles smooth, winged, or setose. Seeds crowned with a tuft of hairs. Stem twining or erect, leafy, rarely leafless, fleshy. Leaves opposite. Flowers rather small, in sessile or pedunculate corymbs, racemes or umbel-like or corymbose cymes, which are subaxillary or lateral between the bases of the petioles.