Osmundaceae

Large, robust, once- or twice-divided fronds arising from a stout, long-lived rhizome, often producing separate fully fertile fronds, or fertile leaflet sections, that look markedly different from the ordinary sterile foliage, turning brown and cinnamon-like with exposed spore clusters.

As true ferns this family has no flowers or seeds — its fertile fronds are so visually distinct from the sterile ones, turning a rusty cinnamon-brown, that they are often mistaken for a completely different plant.