Polystichum imbricans imbricans

Description

The dark green-fronds-of this fern grow 50 to 180 centimetres (1.6 to 5.9-ft) tall, in a tight clump spreading out radially from a round base. They are single-pinnate, with the pinnae alternating on the stalk. Each pinna is 1 to 15 centimetres (0.39 to 5.91-in) long, with a small upward-pointing lobe (a sword hilt, hence the name) at the base, and the edges are serrated with bristly tips. Individual fronds live for 1.5 to 2.5 years and remain attached to the-rhizome-after withering. The round-sori-occupy two rows on either side of the midrib of each pinna and are covered by a centrally-attached, umbrella-like indusium with fringed edges. They produce light yellow spores.