WATEE-PLANTS. 



77 



bristle-like leaves growing round a stem in whorls. Each leaf 

 is divided in forks, three or four times, so making a rather 

 dense mass. The green flowers are also whorled, and grow in 

 the axils of the leaves. The fruit has two horns near the 

 base. The Homwort is useful in an aquarium, and wiU do 



Fig. 56. Common Hornwobt (Ceratophyllum dehersum). 



well if a small portion is tied to a stone and sunk to the 

 bottom. It grows entirely under water, and flowers in July. 



The Bladderwort {TJtricularia vulgaris) (Fig. 57) is a rare and 

 very interesting plant. It is found in some of the ponds and 

 slow-running rivers of the southern and eastern counties of 

 England. Its leaves are divided into hair-hke segments, to which 

 are attached numerous small bladders of a purplish or pinkish 

 colour. The bladders are for the purpose of so buoying up the 



