Pennsylvania and New Jersey have a rich flora with about 3750 recorded species in total, of them about 2200 native. Although a modern flora of Pennsylvania has been published recently (Rhoads & Block, 2nd ed., 2007), as well as a distribution atlas (Rhoads & Klein, 1993) and a website with county data there is no comprehensive, reasonably complete picture collection on the internet or elsewhere available.

While working for two years (mid 2004 to mid 2006) in State College in the chemical industry, I have, with the help of numerous collaborators and with lots of subsequent field trips during business visits until 2012, assembled a collection of more than 2700 species in digital pictures, which represent about three quarters of the total amount. Because of my location in central Pennsylvania , the flora of this part of the state is represented much better. Some European neophytes and adventives are represented by pictures taken in Europe.

The picture size for the database (900 x 1150 pixels maximum) was chosen fairly high, in order to maximize the use of the pictures for identification. Most pictures are between 100 and 300 kbyte in size. We hope that this is acceptable to most internet users with broadband access.

In 2012 a major upgrade was done. Now our website uses a complete checklist and synonymy as provided by the USDA PLANTS database, and the distribution records of BONAP. The New Jersey data have been included, boosting the total from 2800 to 3580 species, and the pictured total from 2100 to 2710 species.

The species have been listed in the database together with some basic information (synonymy, general distribution in Pennsylvania and New Jersey, county records of central Pennsylvania, red list data, habitats, flowering time, etc.), even if no picture is available yet. We hope that other photographers will contribute and donate pictures, in order to create a most complete reference picture collection for the Pennsylvania and New Jersey flora.

There are undoubtedly quite a few initial errors in this database, therefore we would welcome suggestions and corrections.

Michael Hassler, February 2013