Blechnum chilense, the Chilean hard fern or costilla de vaca (Chilean Spanish for "cow's rib"), syn. B. cordatum, B. magellanicum, is a fern of the family Blechnaceae, native to Chile. It is also found in neighboring areas of Argentina and the Juan Fernández Islands. It grows to 0.9–1.8 m (2 ft 11 in–5 ft 11 in), often developing a trunk-like appearance over time. The fertile fronds are more erect, with narrower pinnae, than the infertile ones. This plant has gained the Royal Horticultural Society's Award of Garden Merit.