Introduction to the Notes from Nature Orange County Expedition

Just in time for WeDigBio 2019, the California Phenology Network introduces a brand new expedition of California treasures. This new expedition features specimens from the UC Irvine Herbarium (IRVC). Most specimens were collected in Orange County, California: from its highest point, Santiago Peak (5,678 ft) in the Santa Ana Mountains, to low lying wetlands and coastline. We will also encounter specimens from the broader Southern California region, Southwestern United States, and Baja California, Mexico — lands of arid deserts, foggy coasts, shrubby hills, and rocky mountain slopes.

Orange County is a small, densely populated county in coastal Southern California. At around 800 square miles, it is home to nearly 3.2 million people. Over half of the land area, and thus vegetation, of Orange County has been transformed by human use. However, good examples of almost every vegetation community that historically existed still exist today due to the county’s network of public and private protected areas. Old herbarium specimens can help us get a more complete picture of the historic vegetation of Orange County.

In terms of plant diversity, 1431 species and 1525 taxa, 953 of which are native, are recorded for the county (Roberts Jr, 2008). Dudleya stolonifera and Pentachaeta aurea subsp. allenii are the only county endemics, that is, plants that are limited in range solely to Orange County. The taxonomic focus of our first expedition are the plant families Adoxaceae (elderberries), Aizoaceae (carpet-weeds), Apiacae (carrots), Asteraceae (sunflowers/daisies), and Brassicaceae (mustards).