Ptisana salicina

Ptisana salicina, or king fern, is in the Marattiaceae family. It is native to northeastern Queensland and New Zealand. Its range also spans the South Pacific. Kew places it in the wet tropical biome. It grows in forests and patches of forest that remain. These records cover the wild plant across its native range. They do not show what it needs in a garden.

This fern keeps its leaves year-round. It has a thick rootstock rich in starch. Its fronds can reach 16.4 feet [5 metres] tall. This is its reported size, not a proven garden range. The sources give no separate figure for its spread. They say little about frond shape or colour. A photo caption shows sporangia beneath the fertile fronds. These are the parts that hold spores. The database says growers can raise this fern from spores. It gives no steps or times for doing so.

People have used parts of this fern for food. The stem pith gave them starch in the past. The source says few people now use it this way. It also lists the fleshy rhizome as a vegetable. A rhizome is a stem that grows below ground. People have cooked it by boiling, baking, and roasting. These food records cover the pith and rhizome, not fronds. Useful Tropical Plants rates its food value two out of five. That source lists no known uses as medicine or for other needs.

Past use as food does not prove it is safe. The database lists no known cases of poisoning from this species. This does not prove that all its parts are safe. Its hazard note covers risks found in other ferns. It does not confirm those substances in this species. The facts do not support a firm label of toxic or non-toxic. They give no clear facts about risks to pets.

Loss of habitat threatens this fern in the wild. Mammals brought into its range also browse on it. The source names pigs and goats among the threats. It calls the threat serious but gives no global conservation category. The account names no pests or diseases. It gives no details on how to grow it. There is no tested advice on light, soil, or water. It gives no hardiness zones or firm garden size range. A wet tropical home alone cannot settle these care needs.