This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
Herbs or undershrubs, for the greater part denizens of salt marshes and the sea-shores. Leaves simple, alternate or clustered, exstipulate. Flowers regular, bisexual, in branched panicles, or clustered in involucrate heads. Calyx tubular, plaited, persistent, sometimes scarious and coloured. Corolla monopetalous, with a narrow tube, or composed of 5 separate clawed petals. Stamens 5, epipetalous, or hypogynous in the monopetalous genera. Styles usually 5, rarely 3 or 4. Fruit a 1-celled 1-seeded indehiscent or irregularly dehiscent utricle. Seed pendulous. There are 10 genera, and upwards of 200 widely scattered species.