P. coeruleum: root leaves pinnate, forming dense tufts, and made up of 11-21 lanceolate, entire leaflets; stems erect, 1 1/2-2 feet high, bearing a few small pinnate leaves; flowers in a showy terminal corymbose panicle, blue or white. - Jacob's Ladder or Greek Valerian. - Bushy, hilly places. Fl. July.