Dendrobium is a diverse genus of more than 1000 species of epiphytic (growing on trees), lithophytic (growing on rocks) or (rarely) terrestrial orchids. Distributed throughout tropical and subtropical Asia, the islands of the South Pacific and Australia, they feature elongated, stem-like pseudobulbs bearing linear to ovate leaves. Racemes of showy flowers are produced from nodes along the stems mainly in spring. They can last one day to many weeks, depending on the variety. Many Dendrobiums go through a growth phase and then a rest phase during the year, and must be given water and temperature to match these periods of growth and rest.