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 with opposite entire or pinnatifid leaves and small flowers in dichotomous cymes. Calyx superior, limb lobed or feathery. Corolla funnel-shaped, tube often spurred at the base; lobes 3 to 5, unequal. Stamens 1 to 5; filaments free, slender, exserted. Fruit indehiscent, coriaceous or membranous, with one pendulous seed, and often two empty cells. About twelve genera, and nearly 200 species occur in temperate countries. Valeriana officinalis, a tall plant with pinnate leaves and pink flowers having three stamens, is a common English plant. V. montana and V. didica are dwarf species with pink flowers and entire or pinnatifid leaves.