Bracken (Pteridium) is a genus of large, coarse ferns. It is a prolific and abundant plant in the moorlands of Great Britain, where it is limited to altitudes of below 600 metres. It does not like poorly drained marshes or fen. It has been observed growing in soils from pH 2.8 to 8.6, a wide pH band. Bracken is a pernicious, invasive and opportunistic plant, taking over from the plants traditionally associated with open moorland and has out-competed characteristic ground-cover plants such as moor grasses, cowberry, bilberry and heathers.

en.wikipedia.org/wiki/Bracken