about 7,000 years ago from hybridization between rivet wheat (T. turgidum), a tetraploid, and Tausch's goatgrass (Aegilops tauschii), a diploid.5 In fact, Talbert et al. (1998) say it arose repeatedly as the result of multiple hybridization events. Rivet wheat itself is a much older, natural amphiploid derived from hybridization between two diploid grasses. One was the goatgrass Aegilops speltoides.6 The other was either wild einkorn (Triticum boeoticum) or another wild wheat, T. urartu, more likely the former.7 Another natural amphiploid is Plagiomnium medium (medium plagiomnium moss), shown by Wyatt et al. (1988) to be derived from hybridization between P. ellipticum (elliptic plagiomnium moss) and P. insigne (plagiomnium moss).