In Whey Sike on Teesdale Forest; and in Ditches communicating with Hell Kettles, D.—Mr E. Robson.
169. Potamogeton perfoliatum.
In a Lake, called Dudley Shield, near Nether-Witton, N.—Rev. J. T. Fenwick.
170. Potamogeton densum.
In Ponds at Walker, N. In a Pond at Hebburn; and in the Skern at Darlington, D.
171. Potamogeton lucens.
At Prestwick Carr, Crag Lake, and in the Lake at Dudley-Shield, N.—Rev. J. T. Fenwick. In Whey Sike on Teesdale Forest; and in the Skern, near Darlington, D.
172. Potamogeton crispum.
In Rivulets and Ponds.
173. Potamogeton compressum.
In Ponds at Widehaugh, near Dilston, N. In Stells near Seaton, D.—W. Backhouse, jun.
174. Potamogeton pusillum.
In Ditches near Harton. In Ponds at Lambton, D.-Rev. J. T, Fenwick. In Mordent Carrs, D.—W. Backhouse, jun. At Prestwick Carr, N.
175. Potamogeton pectinatum.
At Hell Kettles, near Darlington, in the River at Chester New Bridge, and in the Wear by Lambton Ferry, D.—Rev. J. T. Fenwick.
Potamogeton pectinatum, var. β P. marinum.—Hudson.
In Meggy's Bourn near Seaton Sluice, N.
176. Ruppia maritima.
In a Salt Water Ditch, called Meggy's Bourn, near Seaton Sluice, N. Near Tees Mouth, D.—Mr E. Robson.
