■ , ON AQUATIC PLANTS, 885 



Utricularia vulgaris (Common Bladderwort) (Fig. 590). — 

 This is an interesting little British plant, having very finely- divided, 



Fig. 588. — Trapa natans. 



Fig. 589. — Fruit of Trapa natans. 



submerged leaves, which are furnished with minute vesicles, or air- 

 bladders. The pale yellow flowers are borne on scapes, which 

 rise about 6in. above the surface of the water. 



Erect=Qrowing Aquatics and Sub-Aquatics. 



When planting on the margins of ponds, tanks, or water- 

 courses, advantage should be taken of the most suitable spots 

 for the introduction of such subjects as are best fitted for them; 

 and this may be determined by a consideration of their heights 

 and habits of growth. The stronger-growing kinds are best 

 adapted for locating in the more exposed situations, arid these 



