Lough Neagh. This great lake, the largest in the British Isles, has low shores, generally stony or sandy, with marshes at the mouths of the streams. The level of the lake was lowered by drainage to the extent of several feet more than half a century ago, since which time some of the characteristic plants have not been seen. Some very interesting species occur. Spiranthes Romanzoffiana, a North American orchid, found also in Co. Cork, occurs in marshy meadows in all of the five counties which border the lake, but nowhere else in Europe. The grass Calamagrostis stricta var. Hookeri is unknown save on the Lough Neagh shores. The sedge Carex fusca (Buxbaitmii), now possibly extinct on Lough Neagh, occurs elsewhere in the British 
Isles only by one lake in Scotland. Certain Highland type plants, such as Lobelia Dortmanna and Isoetes lacusfris, are frequent. The Lough Neagh flora is also interesting as including a group of maritime plants, rare or unknown in other inland stations in Ireland-Cerastium scmidecandriim, Spergularia rupestris, Viola Cwtisii, Erodiiim cicufaritim, Trifolium arvense, Scirpus maritimus, S. Taberncsmontani. In view of the low level of the lake (48 ft. above sea), some of these may possibly be remnants of a maritime flora existing when a depression of the land allowed the sea to enter the Lough Neagh basin. Some rare marsh plants, such as Lathyrus palustris, occur in various places.
