798 THE POPULAR SCIENCE MONTHLY. 



THE LIFE OF WATER PLANTS. 



By M. BUSGEN. 



WHEN we mentally survey the floral dress that variegates 

 the solid crust of our globe, the world of plants appears to 

 be divided into a few large groups. We think of the primitive 

 forest with its mossy trees, the slender vines, and the multiform 

 beauties of the orchids ; the steppe comes to our minds with its 

 hard, sharp-cutting grasses ; and the moist carpeting of the Al- 

 pine flora, with gentian and fragrant herbs. The eye lingers longest 

 on the native group ; the colored population of our meadows rises 

 before us, the forest with its berried undergrowth, and possibly the 

 bushy river bank and the undulating insulated plant-covering of 

 a pond. Each of the plant groups we have named bears a special 

 expression distinguishing it from all the others. The members of 

 each have certain common features the aggregation of which con- 

 stitutes the characteristic of the group. In them are included 

 plants which are not at all connected by natural relationship. 

 Ivy is not related to wintergreen or the strawberry to the huckle- 

 berry, and all these, again, are far removed from ferns, mosses, 

 and fungi ; yet we are satisfied as to the connection of these plants, 

 so that we regard them as members of a definite group, as is rep- 

 resented by our wood flora. So with the other forms we have 

 named, those of the tropical forest, of the steppe, and of the 

 Alpine fields ; the plants constituting them are not grouped by 

 blood relationship. Outer circumstances, the conditions of life, 

 have impressed their special characters upon them. The shadow 

 of the wood, the tropical rains, the short summer of the Alps, the 

 aridity of the steppe all these are factors which have produced 

 in the plants exposed to them common properties more perceived 

 than defined, because they have had effect upon their outer figure 

 as well as upon their vital processes. Thus these groups of plants 

 are developed by the community of their life conditions. They 

 furnish illustrations of Goethe's saying that the manner of life 

 works powerfully on all forms. 



We shall study more closely in this paper one of these com- 

 munities of life conditions the plant world of the water and 

 inquire into the connection existing between its most marked 

 peculiarities and the conditions of life afforded by the water. If 

 we walk along the shore of a large pond sheltering a rich growth 

 of plants, or of a bush-lined stream, the vegetable inhabitants 

 will be divided, at first sight, into three groups the shore plants 

 on the banks ; the floating leaves and flowers of the surface plants ; 

 and in the depths, hardly visible to the eye, the submerged flora, 

 composed of a few curiously shaped flowering plants, and many 



