198 OXFORD: THE UPPER RIVER 



j they will circle out over the stream with plaintive 

 piping, to settle a few yards further on — a manoeuvre 

 ' they repeat a dozen times. Their place is taken now 

 i - " by the yellow wagtail, whose tactics are much the 



same. As beautiful as a humming-bird is Ray's 

 wagtail, and almost as quick upon the wing. They 

 are the constant companions of the Port Meadow 

 cattle, attracted by the swarms of insects that come 

 where cattle feed. 



Let us fasten the painter to this little bridge and 



explore for a few yards this tiny stream. We have 



not time to examine it minutely, but must just 



notice these two plants. They are not rare, but 



are worth noticing because, like the water-soldier, 



/ they are local plants. Among the primulas is one 



T-r . S genus which includes two species only. One is a 



North American, the other an English plant. Here 



— it is — ffoUoma, the waterrviolet, and is flowering very 



late this year. The other we shall not find so easily. 



There, you see that hairy-looking weed floating about 



3/i»t^ ^ in thick bunches. It is Utricularia^ the bladderwort, 



m some respects one of the most interesting of all our 



British plants. Not because of its flowers, which are 



yellow and ordinary, but because of a curious habit. 



It is a carnivorous plant. The little bladders inter- 



