Polystichum setiferum divisilobum AGM
The common name for this fern is the soft shield fern. It's Latin name comes from two Greek words: polys meaning many and stichos meaning a row, referring to the rows of sori (the spore bearing bodies on the underside of the fronds - in this case like bulbils).
Have you noticed that some fronds are under the large stones? This is so that the bulbils come into contact with the soil and so reproduce more plants for our sale table.
Cultivation: just remove dead or damaged fronds if necessary; protect crowns from water logging in winter.