66 NEW YORK STATE MUSEUM 



Similarly a heavy soil, whether glacial till or cretaceous clays 

 (both abundant in central New York), might be equally available 

 as a home for species which require such a mechanical condition 

 for their proper growth. Likewise trees' requiring a merely rocky 

 soil are largely indifferent as to whether the rock is Eozoic granite 

 or Mesozoic trap. 



These principles of soil texture as a determining factor in plant 

 distribution within regions of the same general altitude and climatic 

 conditions are responsible ver}- largely for the characteristic dift'er- 

 ences between the flora of the sandy plains east of Oneida lake and 

 the clay and loamy soils of the surroimding uplands, and explain at 

 the same time the ease with which the species of the northern coastal 

 plain have invaded this territory. 



On hilly clay soil near Tallahassee, Florida, many northern 

 plants occur in a region chiefly sandy and covered by species of 

 the Carolinian flora. This to a certain extent is the reverse of 

 the conditions which exist at the eastern end of Oneida lake. 



Further, if we are to consider the various elements of our flora 

 as having migrated northward after the retreat of the ice sheet of 

 the Glacial epoch, it is apparent that the first advance for^vard of 

 any element of the flora at any time will follow the line of least 

 resistance, which means favorable soil conditions rather than 

 unfavorable conditions where the climatic influences are otherwise 

 identical. The sandy soils of the eastern end of Oneida lake are of 

 alluvial origin (although geologically recent), and hence better 

 adapted to the gro^^i:h of the Austral species of the northern coastal 

 plain than are gravelly drift, clays and cold humus of the northern 

 Alleghanian plateau in New York State. 



With this in mind, the element of Austral vegetation of the region 

 east of Oneida lake as shown in the following list of species becomes 

 of great importance to the student of plant ecology- and plant 

 distribution. 



Dodge's shield fern Dn^opteris simulata Davenp. 



Virginia chain fern Anchistia virginica (L.) Presl. 



CaroUna azolla Azolla caroUniana Willd. 



Shore horsetail Equisetum littorale Kuhlewein 



Ground-pine Lycopodium tristachyum Pursh 



Awned cyperus Cyperus infiexus Muhl. 



Slender cyperus " filiculmis Vahl. 



Spreading spike-rush Eleocharis diandra C. Wright 



Low fimbristylis Fimbristylis geminata ( Nees) Kunt 



Common hemicarpha Hemicarpha micrantha ( Vahl) Britt. 



Long sedge Carex folliculata L. 



Whip-grass = . . . Scleria triglomerata Michx. 



Lindheimer's panic-grass Panicuni lindheimeri Nash 



