1909-1910-] Ponds, and the Life therein, 231 



are no less than four species, — one with a small oval leaf 

 and long rootlet {Lemna minor) ; the second, the great duck- 

 weed {Lemna polyrrhiza) ; the thick duckweed {Lemna gibha) ; 

 and the ivy-leaved duckweed {Lemna trisulca). The large 

 round leaves of the frogbit {Hydrocharis Morsns-rance) may 

 perhaps claim our attention, and as we peer into the pond 

 we may discern the finely divided leaves of the water- 

 milfoil {Myrio'phyllum spicatum). The Canadian water-weed 

 {Anacharis alsinastrtim) is sure to be seen — a plant which, 

 prior to 1847, seems to have been unknown in this country, 

 and is supposed to have been introduced with some timber 

 into the canal at Market-Harborough about that time. It is 

 wonderfully prolific, for a small piece inadvertently dropped 

 into congenial surroundings rapidly increases to such an ex- 

 tent as to become a nuisance and very difficult to eradicate. 

 The pretty white flowers of the water- crowfoot {Banunculus 

 aquatilis) may be observed just peering above the water. 

 The green star-like leaves of the vernal starwort {Callitriche 

 verna) may be seen. It may be noted that this plant is a 

 favourite with newts, which drop their eggs in the narrow 

 leaves. The autumnal starwort {Callitriche autumnalis) is not 

 so likely to be found, as it is not so prevalent, though it is 

 found near London and in some of the northern lakes. If 

 a slow -running stream flows into the pond, the hornwort 

 {Ceratophyllum demersum) may be found, its finely divided 

 leaves giving shelter to myriads of minute creatures. The 

 bladderwort {Utricularia vulgaris), so far as I know, is not 

 found hereabouts,-^ although it is plentiful in the South of 

 England. It is a most interesting plant, with the bladders 

 buoying it up so that the flowers may have the light and 

 heat necessary to their development. Close to the edge we 

 may find some bog moss — a favourite place for rotifers ; or 

 at the bottom of the pond we may come across some of 

 those interesting plants called chara or nitella, or the willow- 

 moss {Fontinalis antipyretica). The flowering rush, reed mace, 

 and many others, may be found, dependent of course upon 

 circumstances. The flora of a pond is full of interest to 

 the botanist, who cannot fail to obtain much information 

 from its study ; while, with the aid of a good microscope, 

 the pleasure of such a study is enormously enhanced, for 



^ [This plant is to be got at Gullane. — Ed.] 



