Pteridium

Pteridium is a genus of large ferns in the family Dennstaedtiaceae. The genus comprises a number of species, including the widely distributed Pteridium aquilinum, commonly known as common bracken, and Pteridium esculentum, the Australian bracken.

These ferns have large, spreading fronds that emerge from creeping rhizomes. Fronds can reach one to several meters in height, are typically evergreen in mild climates, and are highly divided, often described as tripinnate. The sori are near the frond margins, protected by a false indusium produced by the reflexed edge.

Bracken is found worldwide in temperate and some tropical regions, especially in woodlands, clearings, field margins, and disturbed ground. It tolerates acidic soils and can form extensive colonies that spread vegetatively by long creeping rhizomes.

Pteridium species spread vigorously via rhizomes, forming dense stands that suppress other vegetation. They also contain ptaquiloside, a toxin linked to cattle poisoning and, in some cases, cancer risks in humans through contaminated milk or water. Management often requires mechanical removal or herbicides to reduce spread, though eradication can be difficult because of the persistent rhizomes.

In some regions, young fiddleheads of bracken have been eaten after processing, but toxin concerns limit consumption. The plant is sometimes used ornamentally or for erosion control, but its aggressive growth and toxicity make it a poor choice for many landscapes.