The vascular flora and plant communities of Ogle County, Illinois
Since settlement of Ogle County, Illinois, in the early 1830s by Europeans, many botanists have studied the flora of the county. These early studies were restricted to what are now state parks and nature preserves. As a result, the flora of the county was known from only a few locations. The emphasis of the present study was to examine the flora outside of previously described areas and to synthesize the work of previous botanists, resulting in a more complete list of the flora. In addition, the relative frequency of each species and description of the plant communities present are also reported. Completion of the present study results in complete floristic coverage of northern Illinois. Field work began in the summer of 1986 and continued through the summer of 1989. Twenty collecting stations were established and each was visted at least three times during the field season. For each species, voucher specimens were collected and processed using standard herbarium techniques. Notes were made in the field regarding habitat for each species and the presence of those species which were readily identifiable. Information from four herbaria and several published and unpublished papers is also incorporated into the flora. A set of voucher specimens is deposited in the Northern Illinois University herbarium (DEK). The catalogue of the flora includes for each species a botanical name, a common name where one exists, a list of the habitat(s) where found, a statement of frequency, and for rare or otherwise interesting species the locations where found. A total of 938 species representing 414 genera and 103 families is listed. The flora of Ogle County has been significantly altered since settlement by Europeans. Those plant communities which occur on soils well suited to agriculture are now either absent or very rare. As a result, many species which were once common are now infrequent or rare in the county. An effort to preserve what remains of these communities and the species which occur in them is required to insure that Ogle County continues to have a diverse flora.