194 FLOIJ.V OK THE EAST RIDING OF YORKSHIRE. 



1581. Potamogeton polyg"onifolius. Pour., 107. 



Native, Brit., 1-7. June, I\'. 



Common in Holderness drains ; Lambwath stream, 1895*; 

 Skipwith Common, June, 1896 (C.W.). 



1583. P. COloratUB. Homcm., 32. 



Native, Eng., 6, 7. June, I\'. 



Rare. Pools near railway, Market Weighton (J.J.M.)* ; 

 Heslington Fields, near York (C. C. Babington, B. sup.) ; 

 Pond on Barlby side of Skipwith Common (C.W., 1900).* 



1584. P. alpinus. Bulb., 70. 



Native, Brit., i, 2. July, II. 



Common in River Hull and large drains ; sp. confirmed 

 bv Mr. Ar. Bennett. 



1587. P. heterophyllus. Schreb., 71. 



Native, Brit., i, 2. July, I. 



Not common. Ditches near Beverley (B.). Is this the 

 plant of Teesdale's list — " P. palustre foliis inferioribus 

 submersis," &c., &c. ? Lowthorpe, near Driffield, in ponds, 

 Y.N.U. meeting, 1890. 



1590. P. lucens. Linti., 75. 



(Shining Pond-weed). 



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



Fairly common. Market Weighton Canal (J.J.M.) ; also 

 in River Hull and Leven Canal, Holderness.* 



1595- P- perfoliatus. Linn., 93. 



Native, Brit., i, 2. Jul}- 



Rare. Near Beverley (Dr. Hull) ; Hornsea Mere.''' 



I 



