sentences:  In the early 1900s, humans introduced three species of goatsbeard into North America.These species, the western salsify ("T. dubius"), the meadow salsify ("T. pratensis"), and the oyster plant ("T. porrifolius"), are now common in urban areas.In the 1950s, botanists found two new species in the regions of Idaho and Washington, where the three already known species overlapped.