Cyathea is a genus of tree ferns, the type genus of the fern order Cyatheales. They are mostly terrestrial ferns, usually with a single tall stem. Rarely, the trunk may be branched or creeping. Many species also develop a fibrous mass of roots at the base of the trunk. The genus has a pantropical distribution, with over 470 species. They grow in habitats ranging from tropical rain forests to temperate woodlands. The genus name Cyathea is derived from the Greek kyatheion, meaning “little cup”, and refers to the cup-shaped sori on the underside of the fronds.

Cyathea dealbata, commonly known as the silver fern or silver tree-fern, or as ponga or punga is a species of medium-sized tree fern, endemic to New Zealand. It is synonymously known as Alsophila dealbata. The fern is usually recognisable by the silver-white colour of the under-surface of mature fronds. It is a symbol commonly associated with the country both overseas and by New Zealanders themselves. This fern is known to grow to heights of 10 metres or more (though it occasionally takes a rare creeping form). The crown is dense, and mature fronds tend to be about 4 metres long and have a silver-white colouration on the undersides. This distinctive silver colouration has made them useful for laying along tracks for night walking. The fern is known to grow well in well-drained humus, and once established, it will tolerate drier conditions. It does best when sheltered from winds.