Gymnocarpium dryopteris; The Oak Fern has distinct triangular shaped leaves. Basically this impression is caused by the first lateral pair of the main rib of the leaf. These are by themselves triangular shaped (see drawing). The following lateral pairs further suggest the triangular shaped although they themselves are more or less linear shaped. On Iceland it can be found in more or less the same regions as the holly fern, being a broad band around the south-western, western, northern (NW,NE) and eastern coast - from the east southwards to the southern edges of the Vatnajökull. The Icelandic name for this species is Þrílaufungur.