Sometimes you may have trouble accessing a database, whether on campus or off. A link may direct you to a page asking for login information, or payment information.
The University Library has already paid for your access to many databases. If you run into problems, the link may not be running through the proxy server. Try putting the proxy prefix in front of your link - http://proxy.lib.umich.edu/login?url=
Articles can also be obtained through Interlibrary Loan (ILL) if the Library does not have a subscription to a specific journal.
The following databases are divided by topic into Plant Species, General Species Data, Agriculture and Forestry, and General Science/Ecology.
Other resource guides that may be helpful...