National Collection Spotlight: Stiff Star-hair Fern

Delicate in appearance but remarkably resilient, the Stiff star-hair fern (Thelypteris sclerophylla) is a terrestrial, perennial fern recognized by its short, erect stem and striking fronds that can reach up to 50 cm in length. True to its name, the fern’s stems, fronds, and petioles are covered in fine forked, or stellate, hairs that give the plant its stiff, papery texture. On the underside of fertile fronds, round sori release dark brown spores that develop into heart-shaped gametophytes—a fascinating glimpse into the fern’s life cycle.

This globally rare species is endemic to the rockland hammocks of Miami-Dade County, Florida, though its range extends across the Greater Antilles, West Indies, and parts of Central and South America. In South Florida, it survives in just two small preserves, with populations numbering fewer than 300 individuals combined. These ferns thrive in humid, shaded hardwood forests, often anchored to limestone outcroppings with a thin layer of soil. Their survival depends on the stable, moist conditions of this ecosystem, making them particularly vulnerable to threats such as canopy loss from hurricanes and competition from invasive plants.

The stiff star-hair fern is currently safeguarded in CPC’s National Collection by Fairchild Tropical Botanic Garden and Center for the Reproduction of Endangered Wildlife at the Cincinnati Zoo and Botanical Garden, where researchers have developed in vitro spore cultivation methods to support its survival. Continued collaboration and innovative propagation work are critical to ensuring that this rare fern, with its unique ecological role in South Florida’s rockland hammocks, is not lost to extinction.

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