Using morphology and cytology, Ownbey (1950) demonstrated that T. mirus and T. miscellus are allotetraploids (2n = 24) whose diploid (2n = 12) parents are T. dubius and T. porrifolius, and T. dubius and T. pratensis, respectively. The allotetraploids have not formed in Europe, but are native to the Palouse, although their diploid parents are aliens in North America. Because the three diploids did not co-occur in the Palouse prior to 1928 (Ownbey, 1950), T. mirus and T. miscellus cannot be more than ~ 80–90 years old. In fact, the first collections of the allopolyploids were made in 1949. Given that these plants appear to be biennials, the timeframe involved may be fewer than 40 generations. The ancestries of both tetraploids were confirmed through cytology, flavonoid, isozymic and multiple types of DNA studies (Ownbey and McCollum, 1953, 1954; Brehm & Ownbey, 1965; Kroschewsky et al., 1969; Roose & Gottlieb, 1976; D. Soltis & P. Soltis, 1989; P. Soltis & D. Soltis, 1991; P. Soltis et al., 1995; Cook et al., 1998; Symonds et al. 2010; Chester et al. 2012, 2015). Both allotetraploids have been resynthesized multiple times (Ownbey and McCollum, 1953; Tate et al. 2009a). See reviews by Soltis et al. (2004; 2012).
