The Lomatium & Friends website brings together the results of an NSF-funded project to study the diversification of a large clade of Apiaceae from primarily the western United States. This clade, known as the Perennial Endemic North American (PENA) clade of Apiaceae, contains 18 genera and over 200 species (and still counting). Despite its size and importance in the western flora, the evolution of the PENA clade is poorly understood, a fact reflected in the artificiality of its genera. We are developing molecular-phylogenetic hypotheses of the PENA clade using comprehensive sampling of all known species and infraspecific taxa. Our work utilizes molecular, ecological, morphological, and climatic data to clarify the taxonomy and relationships of species within the PENA clade which we will use to provide a revised and updated classification for this group. Given the rampant examples of para- and polyphyly in the PENA clade, extensive reshuffling and renaming of genera and species will be necessary (including new names and many new combinations). The results of this project will be presented in the form of an electronic monograph that will include the updated nomenclature, species descriptions, photographs, specimen records, distribution maps, phylogenetic trees, and links to DNA sequence data, as well as identification guides and keys. The identification tools and species-specific environmental and ecological data provided on this website will aid in future research and in the conservation of the many rare species found within this group. On-line approaches allow for numerous digital images, more detailed and updatable distribution data, and range maps generated from geo-reference data. Interactive and multi-access keys are also more feasible and more user-friendly than traditional keys — an important advantage in a group as challenging to identify as Apiaceae.