Thelypteris noveboracensis, or the New York

New York

New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...

 fern, is a fern

Fern

A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...

 found throughout the eastern United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 and Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

. It is distinctive by its pinnae tapering to the base of the frond, and by its forming extensive clonal colonies on ridgetops and mountain benches. The only other native species in this area with similarly tapering pinnae is the ostrich fern, Matteuccia struthiopteris, which generally grows in riparian habitats. The only other species that forms as extensive clonal colonies is the hay-scented fern, Dennstaedtia punctilobula

Dennstaedtia punctilobula

Dennstaedtia punctilobula is a species of fern native to eastern North America, from Newfoundland west to Wisconsin and Arkansas, and south in the Appalachian Mountains to northern Alabama; it is most abundant in the east of its range, with only scattered populations in the west.It is a deciduous...

.

This fern grows in clumps of three or more fronds along a dark brown, slightly scaly rhizome

Rhizome

In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...

, unlike the very similar Dennstaedtia punctilobula

Dennstaedtia punctilobula

Dennstaedtia punctilobula is a species of fern native to eastern North America, from Newfoundland west to Wisconsin and Arkansas, and south in the Appalachian Mountains to northern Alabama; it is most abundant in the east of its range, with only scattered populations in the west.It is a deciduous...

, which grows in lines. The blade is 8-25" long, yellow-green, and tapers at either end. It produces both fertile and sterile fronds. The fertile fronds are larger and more upright, and produce a few small, round sori near the margins of the pinnae. These sori are covered by a tan, kidney-shaped indusium.

Ecology

Thelypteris noveboracensis is common in sunny patches caused by canopy gaps in mixed woodlands, near vernal seeps, at the edge of swamps, and along streams. Once soil pH levels decline below 4.1, this fern can become a dominant understory species. In such situations, it may outcompete the seedlings of certain tree species, some of which are commercially important. The seedlings of Prunus serotina are especially vulnerable, as the fern releases an allelopathic phenol

Phenol

Phenol, also known as carbolic acid, phenic acid, is an organic compound with the chemical formula C6H5OH. It is a white crystalline solid. The molecule consists of a phenyl , bonded to a hydroxyl group. It is produced on a large scale as a precursor to many materials and useful compounds...

which can kill them.

This fern is a wetland indicator, and an endangered species in Illinois.