There are two species of ‘beech ferns’ that occur in eastern North America. They have traditionally been placed in the genus Thelypteris and this how I treat them here. However, recent evidence suggests inclusion of these ferns in a segregate genus (Phegopteris) instead.
In Broad Beech Fern (Thelypteris hexagonoptera) the lowest pair of pinnae (leaflets) are longer than the second pair. In addition, the rachis is herbaceous-winged throughout. This species forms colonies in moist or dry woodlands.
Broad Beech Fern
In Long Beech Fern (Thelypteris phegopteris) the lowest pair of pinnae are shorter than the second pair and the rachis is no herbaceous-winged between the lower two pairs of pinnae. The fronds also tend to be narrower than those of Broad Beech Fern. This species prefers rocky stream-side habitats and is common along waterways in the Adirondacks of NY.
Long Beech Fern