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.
Shrubs or herbs, often clothed with hispid hairs. Leaves lobed, alternate, or the lower ones opposite. Flowers in gyrate or unilateral racemes or spikes, rarely solitary and axillary. Calyx inferior, deeply 5-lobed, sometimes with appendages in the sinuses. Corolla regular, 5-lobed, campanulate, rotate or funnel-shaped. Stamens 5, inserted on the tube of the corolla and alternating with its lobes. Fruit a 1- or incompletely 2-celled 2-valved capsule; seeds few or many, attached to parietal placentas which sometimes meet in the centre. A small order with about sixteen genera and seventy-five species, chiefly American. The species of Hydrophyllum itself are almost unknown in gardens. They are North American herbaceous plants with large pinnately or palmately lobed leaves and scorpioid cymes of rather small blue or white flowers with bearded stamens. The most familiar genus of this group is