SUBMERGED AQUATIC PLANTS 25 



leaves, which are cut up into thin, linear segments. Pollination 

 takes place under water. Each staminate flower has from twelve 

 to twenty anthers. When mature they contract slightly, and 

 squeeze the pollen into the water. Being of the same specific 

 gravity as the water it does not sink, but is almost sure to reach 

 the stigma, as it is very plentiful. The Hornwort is very fairly 

 common in pools, or slow streams, or ditches near a river, or on 

 the shallow edges of lakes. 



The Whorled Milfoil (Myriophyllum verticillatum) has even its 

 flowers in water, and it inhabits deep, clear water. The Spiked 

 Milfoil creeps and roots in the mud under water, its flowering 

 spike coming above the surface. Both plants have very fine 

 whorled leaves ; the latter is the more common species in Britain. 

 In general appearance the Milfoils are not unlike the Hornworts. 



The Water Soldier (Stratiotes) leads during the greater part of 

 its life a submerged existence. During the winter it remains 

 at the bottom of the pond. When spring comes it rises to the 

 surface, producing fresh leaves, floating roots, and as the summer 

 comes on, flowers. After flowering it sinks again, to mature its 

 fruits and seeds and to develop buds for the production of young 

 plants. Towards the end of August it rises again, the young 

 plants having now grown up, though not yet as large as the 

 mother plant. For a time the parent plant, not unlike an Amer- 

 ican Aloe in appearance, floats on the surface with the younger 

 plants attached ; then the connecting stalks die and decay, each 

 little rosette is liberated and sinks to the bottom, and all hibernate 

 till the following April. This plant is common in the fens of eastern 

 England, and has been found in Lancashire and Cheshire. 



The Water Violet (Hottonia palustris) has the creeping habit 

 of entirely submerged plants, the flowering stems alone coming 

 out of the water. The leaves are submerged and cut up into fine 

 segments, as those of water plants often are The flower-stem 

 bears three to five or six pale purple flowers. This plant belongs 

 to the Primulaceae, and frequents central and eastern England 

 rather than the west. The Water Lobelia (Lobelia Dortmannii] 

 is another aquatic plant that flowers above water. It has tufts 

 of hollow, radical leaves, the dense green carpet of which can be 

 seen through the clear water at the edge of a lake. The leaves 



