Ferns are mostly a tropical group, and New Zealand has an unusually high number of species for a temperate country. We have about 200 species, ranging from ten-metre-high tree ferns to filmy ferns just 20 millimetres long. About 40 per cent of these species occur nowhere else in the world.
Ferns are typically found in moist, forested areas because they require lots of water. Ferns are abundant in all damp situations in New Zealand forests, forming the undergrowth beneath a dense canopy of evergreen trees. They are also found growing on tree trunks and branches and along stream banks. Some hardy species have adapted to other drier habitats such as coastal, alpine, urban and even desert locations.
The leaves of ferns are called fronds and when they are young they are tightly coiled into a tight spiral. This shape, called a ‘koru’ in Māori, is a popular motif in many New Zealand designs.
The Silver Fern or Ponga is a national symbol and is named for the silver underside of its fronds.