Ikebana developed from the Buddhist practice of offering flowers to appease the spirits of the dead. During the 15th century is developed its own identity as an art and several different schools emerged, each with its own set of rules concerning such things as the type of container, number of stems used, other materials used, etc. As with other Japanese arts, only when one has passed an exam and become licensed may he or she teach the particular art form.
Ikebana International's home page
Discussion and photos of different Ikebana schools
A Canadian site that provided the image above.
Dr. Pamental's Home Page || Japan Page