1910] Brunclcen, Studies in Plant Distribution. 153 



springs form the starting point of vegetation. It is quite apparent 

 that the degree of rapidity of erosion is the determining factor in 

 this. The pioneers among the settlers are species with long, creep- 

 ing rootstocks or stolons. Rhus typhina, in many places, sends 

 down its suckers from the upper edge, and in a few places has 

 succeeded in transforming large portions of the bank into thickets, 

 in which it is the decidedly dominant species. Rubus canadensis, 

 in several forms, has likewise managed to establish itself here and 

 there. But the most successful pioneer is Bquisetum aruense, 

 perhaps the most abundant plant of the area, although it is very 

 often killed by having its long rootstocks exposed in the progress 

 of erosion. 



The places which are first covered with a fairly continuous 

 carpet are the upper portions of the erosion tongues and terraces, 

 while the gullies, the vertical top-bank, and the steeper portions 

 everywhere remain still bare or scantily overgrown. The progress 

 of vegetation everywhere tends to counteract the destruction of the 

 bank by washing and landslides, but again and again the erosive 

 forces obtain the upper hand, and the incipient vegetation is de- 

 stroyed. 



Where comparatively stable conditions have existed for some 

 time, nearly all the more common species of the neighboring up- 

 lands begin to establish themselves, most prominent among them 

 being, as usually on newly-colonized areas, those species which 

 have seeds with flying apparatus. In many cases the appearance 

 of species on the bank is not really a colonization, but the first 

 comers were bodily transferred from the upland by landslides. 

 This seems to be especially true of many patches of Poa and other 

 pasture grasses, which are now covering the larger erosion ter- 

 races. 



Among the herbaceous species commonly found on the stabler 

 portions of the bank, and which are abundant on the neighboring 

 uplands, are the following: Several species of Solidago, Aster 

 and Erigcrou: Rudbeckia hirta, Asclepias syriaca, Verbascum 

 ihapsus, Melilotus alba, Trifolium pratense and Trifolium repens, 

 Cirsium arvense, Taraxacum officinale, Blymits canadensis, Phy- 

 salis pubescens. Added to these are some species usually found 

 along the Lake Shore, but absent inland : Artemisia canadensis, 

 A. caudata, Lathyrus maritimus; finally there isPsoralea onobry- 



