This is the Taiwanese variety of Oriental chain fern, collected in the mountainous forests of Taiwan by Dan Hinkley in 1999 (collection number DJHT.99015). The common name is derived from the chain-like arrangment of sori (spore-producing organs) on the underside of the leaves (not seen here).
As I find this plant both structural and photogenic, I’ve taken a number of photographs of it in the past. Other attempts can be seen here: Woodwardia orientalis var. formosana via the UBC Botanical Garden Forums.
Photography resource link: Converting Images from Colour to Greyscale. Darwin Wiggett explores some techniques in Photoshop for converting colour images to greyscale. I’ve used the “Blending Two Channels” technique for today’s photograph, with a red-red channel multiplication at 100%.