230 TYPICAL EXAMPLES OF PLANT SUCCESSION 



three stages are like those of the normal succession but in the fourth 

 stage a quaking bog is formed. This consists of a floating mat of 

 vegetation which is held together by a network of roots and rhizoids 

 of sedges and other plants and may extend out over the surface of 

 the water for some distance. The mat appears like solid ground but 

 walking upon it is like walking upon India rubber for it is depressed 

 at each step and then springs up again so that one actually walks in 

 several inches or more of water. Upon this floating mat are found 

 many of the typical bog plants such as Sphagiium moss, cranberry 

 (Vacciniwn) , the pitcher plant (Sarracenia) the sundew (Drosera), 

 etc. As the mat becomes more stable and somewhat drier through 

 the accumulation of dead organic matter the shrub stage appears. 

 The first shrubs are usually the dwarf birch {Betula ■pmnila), the 

 leather-leaf {Chavmdaphne calyculata), the bog rosemary {Andro- 

 meda polifolia), and the swamp blueberry (Vaccinium corymhosum), 

 and they are followed later by such taller shrubs as the winterberry 

 {Ilex verticillata) and the poison sumach {Rhus vernix). The first 

 tree to appear on the bog is usually the tamarack {Larix laricina) 

 which is followed later by spruces at the north, or deciduous trees 

 at the south, and finally by the climax trees of the region. 



The swiftly-running water of a young stream presents conditions 

 that are unfavorable to most plants and the succession does not 

 progress beyond two or three stages until the stream becomes more 

 mature and the water more sluggish. Some of the plants that are 

 found in the young stream are Cladophora and some other algae, 

 mosses of the genus Fontinalis, and some species of pondweeds and 

 saxifrages. The later stages which finally take place in an old stream 

 are very similar to the later stages in standing water. 



REFERENCES 



Bray, William L.: History of Forest Development on an Undrained Sand 

 Plain in the Adirondacks, New York State Coll. Forest. Tech. Publ., 13, 

 47, 1921. 



Cooper, W. S. : Plant Succession in the Mount Robson Region, British Colum- 

 bia, Plant World, 19, 211-238, 1916. 



Vegetation Development Upon Alluvial Fans in the Vicinity of Palo 



Alto, California, Ecology, 7, 1-30, 1926. 



Croxton, W. C: Revegetation of Illinois Coal Stripped Lands, Ecology, 9, 

 155-175, 1928. 



EwiNG, J. : Plant Succession of the Brush Prairie in Northwestern Minnesota, 

 Jour. Ecol., 12, 238-266, 1924. 



Forest, H. de.: The Plant Ecology of the Rock River Woodlands of Ogle 

 County, Illinois, Trans. Illinois State Acad. Sci., 14, 152-193, 1921. 



