Aza'lea, a genus of plants belonging to the heaths, remarkable for the beauty and fragrance of their flowers and distinguished from the rhododendrons chiefly by the flowers having five stamens instead of ten. Many beautiful rhododendrons whose leaves fall once a year are known under the name of azalea in gardens. Azaleas are common in North America. An Asiatic species, famous for the stupefying effect which its honey is said to have produced on Xenophon's army is also common in gardens and shrubberies, and another is a brilliant greenhouse plant.