192 FLORA OF THE EAST RIDING OF YORKSHIRE. 



1569. Lemna polyrrhiza. Linn., 59. 



(Greater Duckweed). 



Native, Eng". , 1, 2, 6, 7. July I. 



Frequent. Ponds near Beverley (B.); old fish ponds at 

 Swine (J. W. Boult)* ; Hornsea (C.W.)*; near Selby(W.N.C.). 



ALISMACEyE. 



1 57 1. Alisma Plantag-o-aquatica. Linn., 100. 



(Water Plantain). 



Native, Brit., 1-7. July II. 



Very common in all dykes. 



1572. A. ranunculoides. Linn., 87. 



(Lesser Water Plantain). 



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



Frequent in similar localities to the above. Inglemire 

 Lane (G.N.) 1850; Kelsey Hill Ponds (C.W.); Salt-Ings and 

 Dunswell Lane dykes (J.F.R.); Skipwith Common (W.N.C. ); 

 near Howden (J.B.). 



1573. Elisma natans. Buchen, 14. 



(Floating Water Plantain). 



Native, Local, Incognit. 



Very rare. In the "Lake at Hornsea" (R.T.), now 

 probably extinct, as it has onl)- been once seen since Tees- 

 dale's day (B. sup.). I doubt very much that it has ever 

 existed in the E. Riding. 



1574. Sagittaria sagittifolia. Linn., 58. 



(Arrowhead). 

 Native, Eng., 1-7 Aug., II. 



Common in dykes near Beverley (Dr. Hull), Spring dyke, 

 Hull, where it still grows*; Beverley (B.); Dunswell, and in 

 many Holderness drains and dykes, e.g., near Brandesburton, 

 Sutton, and Keyingham. 



