FLORA OF THE EAST RIDING OF YORKSHIRE. I95 



1596. Potamogeton crispus. Linn., 94. 



(Curled Pond-weed). 



Native, Brit., i, 2, 5, 6, 7. July, I. 



Common in drains and dykes, var. approaching serratus, 

 Huds., not uncommon near Hull*; River Derwent (B.). 



1597. P. denSUS. Linn,, 59. 

 (Opposite-leaved Pond-weedj. 



Native, Eng., i, 2, 6, 7. July I. 



Very common in Holderness*; in the River Derwent (B.); 

 near Selby (W.N.C.). 



1598. P. zostersefolius. Schum., 20. 



Native, Eng., i, 2. 



Near Beverley (B.) ; very likely in our drains, but not 

 identified of late. 



1600. P. ObtUSifoliUS. Mert. and Koch., 54. 

 (Grassy Pond- weed). 



Native, Eng., i, 2. June, III. 



Not common. Drain within borough of Hull, near New- 

 land Avenue*; as " compressus," near Beverley (Dr. Hull) ; 

 open drain in Hull (C.W., 1901). 



1601. p. Friesii. Rupr., 47. 



Native, Eng., 2. July, I. 



In a dyke west of Hull, 1896* ijide Mr. Ar. Bennett) ; 



also an undetermined hybrid (?) in pond at Marfleet near 

 Hull, 1900.* 



1602. P. pusillus. Linn., loi. 

 (Small Pondweed). 



Native, Brit., i, 2, 6, 7. June, IV. 



Ponds near Beverley ; Kelsey Hill (C.W.) ; a much 

 attenuated form near Bromfleet* ; Selby (W.N.C.). 



