SEAWEEDS AND THE WATER-FLORA. 1 89 



accurate observation. If one were to suppose oneself 

 about an inch in height and standing on the mud 

 amongst the reeds, the water would seem to be crowded 

 with thick stems and branches. From the upright ones, 

 graceful floating ribbons and streamers of green Algae 

 would hang waving in the currents. Masses of jelly- 

 like Algae containing green or blue cells would be 

 attached here and there. Every branch and stem, as 

 well as the whole muddy floor, would be covered by a 

 crust of golden-brown diatoms, forming a continuous 

 and uninterrupted coating. Some would be attached 

 to elegant stalks of transparent jelly; many would be 

 dead and transparent, allowing their delicate lines and 

 striae to be distinguished. Floating on the surface 

 above would be little colonies of Lemna ; and, perhaps, 

 floating Algae, such as Oscillatoria. Even the water 

 itself would be occupied by scattered, free floating 

 diatoms, moving about with their peculiar screwing 

 motion, as well as by an infinite variety of waterfleas, 

 water shrimps, and other living creatures. 



Moreover, the interlacing of upright and horizontal 

 branches near the edge of the water forms a sort of trap 

 for silt. Dead leaves and fallen branches, etc., collect 

 in this entanglement, and the formation of organic 

 matter proceeds rapidly. After a very few seasons, the 

 mud has so risen that the water is sufficiently shallow 

 for Rushes and Iris to develop. Then their leaves and 

 the floating silt, etc., will give sufficient foothold for the 

 marsh plants and these will eventually give place to the 

 ordinary land vegetation. 



Canals and rivers often show, in backwaters and in 

 very gently flowing parts of their course, the same general 

 succession ; but, sometimes, special plants are to be found 

 in these backwaters. Thus, for example, the little bays 



