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 shrubs with alternate or-sub-opposite entire or pin-natisect leaves and regular pentamerous flowers. Calyx inferior, 5- or rarely 4-lobed. Corolla regular or slightly unequal, hypogynous, usually 5-lobed, plaited, imbricated or valvate in aestivation. Stamens free, of the same number as the corolla-lobes, and alternate with them. Fruit usually 2-celled, capsular or baccate, rarely 4- or many-celled. Seeds many, albuminous, usually kidney-shaped. This is a large and important order, comprising about 50 genera and upwards of 1,000 species, the greater part from tropical countries. Amongst the useful species we may quote the Potato (Solanum tubero-sum), and Tomato or Love-Apple (Lycopersicum esculentum). It is worthy of remark, too, that many of the members of this family are virulently poisonous.