Ownbey's Tragopogons: 40 Years Later

Two of the classic examples of recent allopolyploid speciation are Tragopogon mirus and T. miscellus. Previous studies have documented that both allotetraploids originated within the past 50–60 years; the diploid parents of T. minis are T. dubius and T. porrifolius; those of T. miscellus are T. dubius and T. pratensis. It has now been 40 years since these allotetraploids were first described by Ownbey in 1950. To assess whether population size (the absolute number of plants) and population number of these species have changed during the past 40 years, we determined their distribution and numbers in the Palouse region of eastern Washington and northern Idaho in the spring of 1990. We visited 90 localities, 60 in Washington and 30 in Idaho. Tragopogon minis is found in nine locations, with eight of these sites located in eastern Whitman County, Washington. Tragopogon miscellus is much more widespread, occurring in 38 of 90 locations. The latter species is now one of the most common weeds in the vicinity of Spokane, Washington. Comparison of the current distributions of these species with historical records indicates that both allotetraploids, especially T. miscellus , have increased substantially in both geographic range and numbers. These Tragopogon species offer an excellent model system for testing questions concerning the ecology and population biology of recently derived allotetraploid species and their diploid progenitors.