leaves also eliminates both P. angustifolius and P. lucens. 
The leaf-shape, the venation, the flat and blunt apex, and the 
distinctive colour are those of P. alpinus. Mr. Wallace’s 
plants, however, afford additional and conclusive evidence 
of the correctness of the name they bear, for on several of the 
sheets there were both floating leaves and spikes of mature 
fruits, each quite distinct from those of any other British 
species and unquestionably those of P. alpinus. So far as my 
experience goes, this is the first time such complete and 
valuable proof has been available. — W. H. Pearsall. 
Potamogeton lanceolatus Sm. Penrhos Lligwy, Anglesey, 
v.c. 52, Aug. 3, 1910. — R. H. Goode., comm. G. Goode ( Fide 
A. Bennett). This is still given in the L. C. list as a species 
although Hagstrom (Grit. Res. 1916, 149) showed conclusively 
that the plant was P. alpinus x pusillus. Fryer and Bennett 
considered it to be the hybrid P. heterophyllus X pusillus. As 
both these species possess leaves with a cuspidate apex, that 
character would inevitably appear in the hybrid, but on the 
contrary all its leaves have the margins at the actual tip 
convex. This gives the leaves the blunt appearance which is 
so characteristic of P. alpinus. Moreover, the lateral nerves 
near the apex, in both heterophyllus and alpinus , follow the 
curve of their respective leaf-margins — so to speak — in 
heterophyllus joining the midrib with the outer curve concave, 
and in alpinus with it convex. In P. lanceolatus the lateral 
nerves turn suddenly inward (with a sharp convex curve) to 
the midrib, as in alpinus. Lastly, in heterophyllus the blade 
of the floating leaves is usually shorter than the petiole which 
is often very long (8cm.). In P. lanceolatus the blade is always 
longer than the petioles. — W. H. Pearsall. 
Potamogeton gramineus var. fluvialis Fries. In deep water 
in the Basingstoke Canal, near Frimley, Surrey, Sept. 13, 
1931. — E. C. Wallace. Correctly named. — W. H. Pearsall. 
Potamogeton lucens L. Marsh ditches at Iford, Ouse Valley, 
East Sussex, July 5, 1931. — E. C. Wallace. Clean and 
beautiful specimens of typical P. lucens, a species which is 
partial to calcareous waters and therefore often encrusted. — 
W. H. Pearsall. 
Potamogeton lucens L. Wey Navigation canal, near Send, 
Surrey, July 11, 1931. Plants six to ten feet in length, very 
