170 TRANSACTIONS OF THE [ Sess. LXXV. 
Malaxis, and Siw latifolium as bemg our most striking 
Umbellifer, but we might point to Cicuta virosa as an 
equivalent to the latter in the Borderland marshes, to 
Malachium aquaticum as taking the place with us of 
Stellaria nemorum, and Veronica anagallis of V. Becca- 
bunga. Cardamine amara is a woodland plant to a great 
extent in the North; with us it occurs in the Fen willow- 
holts; but once more it behoves us to remember that the 
fen country was once well-wooded. We have Utricularia 
vulgaris and U. minor in some quantity, but no U. inter- 
media; we have Parnassia but little Pinguicula or 
Drosera, Hippwris is plentiful and is apt to take the 
place of Equisetum, while we have no E. sylvaticum or 
E. hyemale at all. Myrica Gale cannot be relied upon as an 
instance, as, though now almost extinct, it is said to have 
once been plentiful in the Fens; but the genus Eriophorum 
is certainly conspicuous by its absence at the present day, 
and was apparently always rare with us. Lastrea Thely- 
pteris is, moreover, the only Fern of the Level, and in these 
two cases we again note a great difference from the marshes 
of Scotland. 
The genus Potamogeton provides many interesting forms 
for the botanist to study, and has been ably worked out of 
late years by Mr. Alfred Fryer of Chatteris, who lives in 
the midst of the Fen country. We lack many of the 
Scottish species, notably P. alpinus (=rufescens) and 
P. polygonifolius—the place of which is entirely taken by 
P. coloratus ( =plantagineus),—but we are rich in forms of 
P. Zizi, P. heterophyllus, and so forth, while P. Billupsi, 
P. faleatus, and P. crassifolius have been determined as 
new species by Mr. Fryer, and P. fluitans, P. decipiens, and 
P. lanceolatus are only known from a few other counties. 
In conclusion, we may mention the effect of salt water in 
the Fen area, which extends far above the actual influence 
of the tide. This is shown by the presence of Scirpus 
maritimus at Upware, south of Ely, and at Sutton, on the 
washes of the Bedford Rivers: while Juncus Gerardi has 
been found in the latter district, and a form of J. com- 
pressus, possibly derived from the same stock, accompanies 
Carex distans in a field where sea-shells are commonly met 
with, at Waterbeach near Cambridge. 
