Pityrogramma calomelanos aka Dixie Silverback Fern

Pityrogramma calomelanos is a small fern. It belongs to the Pteridaceae family. The RHS calls it silver fern. Its home range starts in Mexico and spans tropical America. This takes in Central America and the Caribbean. It also covers much of South America. It reaches Argentina and Paraguay in the south. It is not native to Britain or Ireland. The RHS gives an older name, Gymnogramma calomelanos, too.

The fern grows about 1.3 feet [0.4 metres] tall. Kew calls it rhizomatous or rock-growing. Rhizomatous means it grows from a creeping stem. Its fronds have pale, whitish undersides. Young fronds uncurl from a crozier, a curled tip. Fertile fronds bear spores that form on their undersides. The source says growers can raise it from spores. It gives no mature width or full frond shape details. Its captions point out the clear, pale undersides.

This fern grows in the tropics and subtropics. Useful Tropical Plants places it at low to middle heights. Ecuador records range from sea level to 8,200 feet [2,500 metres]. One photo shows it by a South African mountain track. It grows there on disturbed soil, beyond its home range. The source also shows a plant growing in Malaysia. It has become invasive in parts of the tropics. This matters when weighing its place in a garden. The sources give no limits for light, watering, soil, or frost.

Most recorded uses concern folk medicine, not food. People put leaves on wounds, cuts, ulcers, and bleeding sites. They crush leaves to make a poultice, or moist dressing. People have used leaf infusions for bronchitis, colds, and stomach pain. Other records note use for asthma and several serious lung diseases. One record lists the root as a cough treatment. In Guyana, people use water extracts for sexually transmitted disease. Records also list whole-plant infusions for bleeding and male sexual stamina. These reports describe folk practice. They do not prove that the treatments work.

Useful Tropical Plants lists no known food or other uses. It gives no toxicity records for this species. This lack of records does not mean eating it is safe. The source warns that some ferns can pose hazards. It does not confirm those hazards in this species.