Experimental hybridizations of Eriophyllum annuals (Asteraceae, Helenieae).

Seven of the eight annual species of Eriophyllum, a western North American genus, were studied in greenhouse and garden. Eriophyllum congdonii and E. nubigenum proved to be self-compatible; E. ambiguum, E. multicaule, E. pringlei, and E. wallacei were self-incompatible; E. lanosum was not studied. All combinations of artificial hybridizations were attempted except E. congdonii × E. lanosum. Among the species with n = 7, fertile hybrids came from E. congdonii × E. nubigenum and sterile hybrids from E. ambiguum var. ambiguum × E. pringlei, E. ambiguum var. paleaceum × E. congdonii, E. multicaule, E. nubigenum, and E. pringlei, as well as E. multicaule × E. congdonii and E. multicaule × E. pringlei. The other homoploid combinations failed, as did heteroploid combinations involving the annual species with n = 7 and either E. wallacei (n = 5) or E. lanosum (n = 4). Sterile hybrids were generated in crosses of E. congdonii to the perennial E. lanatum (x = 8).