The purpose of this study was to provide an introductory analysis of the content of the Web sites of botanical and horticultural libraries in the United States to determine what types of resources and information is included, whether or not information is organized and accessible, and to what extent botanical and horticultural libraries are using the Web to exhibit rare book collections. The population for this study included libraries with membership in the Council on Botanical and Horticultural Libraries as well as libraries listed in "The Directory of Special Libraries and Information Centers" whose primary subject scope covered botany, horticulture and related subjects. Thirty-seven Web sites were evaluated, and data were collected assessing background information, authority/currency/accuracy, features to promote indexing by search engines, navigation/functionality, organization/format, access for different browsers/systems, access for different user groups, basic library information, and additional features. Comparisons were made based on parent organization type, collection size and number of pages in each site. Results showed that most sites provided information on collections, hours, contacting the library, and services and policies, but less than half included link lists or mission statements. Service information and additional features present varied by library type. Lose frequencies in most of the design categories indicated that many of the libraries were not following design recommendations for organization and accessibility. The inclusion of rare book exhibits by eight of twenty-two libraries mentioning a rare book collection suggests that United States botanical and horticultural libraries have only begun to use the Web for this purpose. Appendices include the data collection instrument, frequency tables, library Web sites evaluated, and library type categorizations. (Contains 32 references.) (AEF)