Athyrium distentifolium commonly known as Alpine Lady-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 in widely in the Northern Hemisphere

Northern Hemisphere

The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...

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It is a common upland variety above 600 metres in the Highlands

Scottish Highlands

The Highlands is an historic region of Scotland. The area is sometimes referred to as the "Scottish Highlands". It was culturally distinguishable from the Lowlands from the later Middle Ages into the modern period, when Lowland Scots replaced Scottish Gaelic throughout most of the Lowlands...

 of Scotland

Scotland

Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

, with more than 10% of the UK population being found in the Cairngorm mountains

Cairngorms

The Cairngorms are a mountain range in the eastern Highlands of Scotland closely associated with the mountain of the same name - Cairn Gorm.-Name:...

, especially on scree slopes in Glen Feshie, and on Ben Avon

Ben Avon

Ben Avon is a mountain in the Cairngorm mountains of Scotland. The highest point of the massif, known as Leabaidh an Dàimh Bhuide is classified as both a Munro and a Marilyn....

, Ben MacDui and Beinn a' Bhùird

Beinn a' Bhùird

Beinn a' Bhùird is a Munro in the Cairngorm mountain range of Scotland.In Watson the author suggests the mountain should be named Beinn Bòrd - table hill saying that local Scottish Gaelic speakers pronounced the mountain Paing Bòrd, with some of the older local folk still using Painna Bòrd.The...

. Regarded as nationally scarce, it is a snow-tolerant species. The stunted form var flexile

Athyrium flexile

Athyrium flexile, commonly known as Newman's Lady-fern, is a fern endemic to Scotland.It is an upland variety typically found above 750 metres on screes made up of siliceous rocks such as quartzite and granite in the Highlands where it is found at only four sites...

, which is found at 750 metres and above, is found at only 4 sites and is endemic to Scotland.

The sub-species americanum is found in the western United States

United States

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

, Alaska

Alaska

Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

, 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...

 and coastal Greenland

Greenland

Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...

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