396 Tlie New York State College of Forestry 



"On Staten island are found such Austral plants as sweet gum, 

 persimmon, mistletoe, willow oak, etc. On Mount Marcy, arctic 

 species, such as Diapensia lapponica, Rhododendron lapponicum 

 and a score of other species whose distribution is throughout the 

 arctic regions of the three northern continents extending south- 

 ward only on high mountains. This is much the sort of difference 

 that one would get as betAveen southern Illinois and Hudson bay. 

 It supports the suggestion that within New York State there may 

 be recognized a right wide range of floral provinces. But I wish 

 to caution the reader against accepting without qualification the 

 alleged facts of temperature effect as determined by elevation. 

 Many of the phenomena of distribution will be found correlated 

 with soil conditions, slope and exposure, local air drainage, etc., 

 so that in reality the local edaphic conditions must be known." 



We have seen that much of the terrain of New York State, more 

 particularly the central plateau area, falls in the region where 

 southern or Austral plants commingle with northern or boreal 

 forms, that is, in the Transition Zone of Merriam. But the topog- 

 raphy of the State and the proximity of certain parts of it to the 

 ocean and the Great Lakes have brought about decided changes 

 in zonal relations. For example, the dissection of the interior 

 plateau by north-south drainage channels has led to a northern 

 extension of Austral trees. This is especially well evinced in the 

 Hudson Valley, where oak, chestnut and hickory persist more or 

 less strongly, to Glens Falls and Whitehall, likewise in the drain- 

 age systems of the Delaware, Susquehanna and Alleghany rivere. 

 The Great Lakes, owing to their ameliorating effect on climate, 

 permit of the Austral flora along their southern shores. In the 

 case of Lake Ontario this zone extends south into the Finger Lake 

 region while the transition from Austral to Transition zone is 

 abrupt south of Lake Erie owing to the more rugged topography. 

 At higher altitudes in the Adirondacks and Catskills a more rigor- 

 ous climate prevails and provides for a southern extension of the 

 boreal vegetation of the Canadian zone in the form of islands sur- 

 rounded by plateau lands, the chain of such islands being con- 

 tinued southward at increasing elevations in the Appalachians 

 and providing, as it were, a north-south bridge for the extension 

 of, or the persistence of boreal plants far to the south, in the last 

 case laggards in the march of vegetation northward following 

 glaciation. 



In conclusion we may say that while — judged by latitude 

 and theoretical temperature alone — the terrain of New York 



