The beginnings of a new Pteridium aquilinum frond already show the sturdy, angular stem and short, finger-like leaflets on tertiary branchings. It also presents several fleshy, worm-like beginnings of frond-parts, densely coiled and covered in silver grey hairs.
These less advanced components are still compactly curled up for later unfolding. By then the frond will be hard and hairless, all the small tips straightened.
The eagle fern, one of the plant’s common names, grows to heights from 1 m to 2,5 m, the main stem or stipe up to 1 cm in diameter. The rhizomes can grow as deep as 3,5 m.
The mature frond shape is roughly triangular. The plant is characterised by dense stands. It is winter deciduous (Bean and Johns, 2005; Wikipedia; iNaturalist).