The Bryoflora of the Genesee Country, New York 3. A Preliminary Survey of the Bryophytes of Orleans County

Abstract

One hundred twenty-three taxa are reported from Orleans County in west-central New York. This is the first report of bryophytes from this county. Orleans County represents the northwest corner of the area treated in our study of the bryoflora of the Genesee Country of New York (Ehrle & Coleman 1963) started in 1960. Collections in the county have been made at from one to four sites in areas corresponding to each of the eight quadrangles of the U.S. Geological Survey topographic maps. The geologic history of Orleans County has its base in the upper Ordovician and extends into the Silurian. The bedrock is sedimentary, largely calcareous shales and sandstones, a coarse dolomite, and Salina shales. The county has been heavily glaciated but there are no extensive drumlins as in the counties to the east and south (Alteri & Coleman 1965). South of the Road, which approximates the shoreline of glacial Lake Iroquois (Fairchild 1925), there are a number of long northeast-southwest-oriented gravel undulations, indicative of the termination of drumlinization (Fairchild 1929). In the Pine Hill area the gravel hills and two late-stage bogs are glacial phenomena associated with the Eagle Harbor Esker where it terminates in the Barre Moraine (Giles 1918). Topographic features here 1We thank Dr. E. H. Ketchledge and Mrs. Charlotte Alteri for help with certain determinations. We each have one set of specimens and a third set is in the State Museum in Albany. 2 231 NorthLMain Street, Albion, New York. 8 Department of Biology, University of Rochester, Rochester, New York. This content downloaded from 157.55.39.197 on Sun, 11 Dec 2016 04:55:53 UTC All use subject to http://about.jstor.org/terms 19661 LYMAN & COLEMAN: NEW YORK BRYOPHYTES 119 resemble those of the kame, kettle, and esker topography in the Mendon Ponds area of Monroe County. Extensive swamps and muck farmlands in the southern part of Orleans County and northern Genesee County are purported to be the bed of glacial Lake Tonawanda. North of these swamps, farms stretch across the county to the Erie Barge Canal and then on to the Road. The Ridge is some 20 to 40 feet higher than the flat, sandy plains extending beyond it to Lake Ontario. These, also in cultivation, are interrupted only by the four major creeks of the county and their tributaries. Orleans County has certain limitations of habitat for bryophytes. There is little diversified terrain and most of the county has been cultivated for at least the last 50 years. The result of continued agriculture is few undisturbed environments for native vegetation. An additional factor limiting local bryophyte populations may be the relatively dry climate. Orleans County has the lowest average annual precipitation of the counties of the Genesee Country. Its 26.59 inches contrast strikingly with the highest precipitation, 37.71 inches, in Livingston County (Yearbook of Agriculture 1941). From 1960 through 1964 a total of 554 collections of bryophytes was made at 19 collecting sites in the county. Collecting was random, no specific ecological study having been attempted in this initial