NOTES ON OXFORD PLANTS. 227 



no danger of confusing it with any other species, and, as it is in 

 active growth throughout the year, it affords matter for almost 

 daily observation. Perhaps no botanist, however skilful, can grasp 

 tbe idea of a "species" in the genus Potamogeton who has not 

 watched the growth of some one form throughout one year at least. 

 At the end of that time he will have been able to observe enough 

 of the wonderful changes these plants undergo to enable him to 

 correct to some extent the false conclusions to which such dried 

 specimens as are usually found in herbariums would otherwise 

 infallibly lead him. 



P. crispus is abundant throughout all the Fen-land water, and 

 is probably to be met with in every county in Great Britain. 



NOTES ON OXFOED PLANTS. 

 By G. Claridge Deuce, M.A., F.L.S. 



Four years having elapsed since the publication of the Oxford- 

 shire Flora, it may be well now to place upon record some of the 

 additions which have been made. 



For the Ouse district, which had been imperfectly explored, 

 Mrs. Worley sent a list of plants noticed by her about Hethe, which 

 included some interesting species. Two of them, Genista avglica 

 and Vaccinium Myrtillus, I have hitherto not been fortunate enough 

 to meet with in the county. They are exceedingly rare in the 

 locality where they were noticed by Mrs. Worley, relics probably of 

 an ericetal vegetation now almost destroyed. 



The species additional to the county are marked *. The 

 numbers following the localities denote the divisions, as defined in 

 the ' Flora.' 



Adonis autumnalis L. Colonist. Cottesford, Mrs. Worley, 2. 



Ranunculus acris L., var. multifidus DC. Chinnor 7. — R. 

 Flammula L. Cottesford, Mrs. Worley, 2. — Var. latifulius Wallr. 

 Headington Wick, 4. — Var. ovatus DC. Pond near Nettlebed, 7. — 

 U. heterophyllus Web. Pond near Witney, 5. 



Helleborus viridis L. Our plant appears to be the H. occidcntalis 

 Reuter, the glabrous form of aggregate H. viridis L., but which, 

 perhaps, may be better described as var. occidentalis (Reut.). 



Delphinium Ajacis Reich. Bay swater, Rev. F. Woods. Plentiful 

 in a field near Summertown, 4. 



NigeUa damascena L. Casual. Corn-fields near Hethe, Mrs. 

 Worley, 2. 



Nymphaa alba L. Was first recorded as an Oxford plant in 

 Lobel, 1570. 



Papaver Rhaas L. — Var. Pryorii milii is not infrequent on sandy 

 soils as at Headington, 4 ; Radley, ; Ipsden, Goring, and Barton, 

 7. A plant with decumbent stem and pale flowers is probably the 

 var. Roubiaei Vig. It occurred on waste ground near the gas- 

 works, Oxford, 5. 



