Pittsburgh Weed: collected 149 years ago

​Some species are well adapted for life in the Anthropocene, commonly found in novel, human-made habitats such as roadsides, sidewalk cracks, farm fields, dumps and industrial sites.  One such plant species that particularly well suited to city life is “quickweed” (Galinsoga quadriradiata). It has many common names, including “Peruvian daisy,” “shaggy soldier,” and “fringed quickweed.” In fact, the species was once known locally as “Pittsburgh weed.” To our knowledge, this is the only example of a non-native species that was first recorded in North America in Pittsburgh (or at least among the earliest). It was introduced here from South America sometime in the mid-1800s.  Pittsburgh weed was first discovered by the courthouse in Pittsburgh by Judge John D. Shafer (1848-1926), a prominent lawyer and dean of Law School of the Western University of Pennsylvania (now University of Pittsburgh). An avid botanist, Shafer was also a founding member of the Western Pennsylvania Botanical Society. The specimen pictured here is one of the earliest (if not the earliest) specimen collected in North America, well outside its native range. It was collected 1869 in along the “Ridge St” railroad tracks in Allegheny City, which has since been annexed by Pittsburgh (now the North Side).  Keep a look out for this interesting species throughout the city, especially along sidewalk cracks and at the base of street signs and electric line poles.  It is now a common weed, and can be found in nearly every major city all over the world.

Below: Close up of original specimen label from the earliest collection (that still exists) of the species in Pittsburgh, collected in 1869.

Below: "Pittsburgh weed" (aka "quickweed") taken on October 13, 2017 in the lawn near the Carnegie Museum of Natural History.