Allopolyploid taxa can exhibit various combinations of parental traits. Two fawn-lilies, Erythronium elegans of western Oregon and E. quinaultense of northwestern Washington, are thought to be allotetraploid derivatives of the same two species, E. montanum and E. revolutum. For multiple populations of all four species, we obtained sequence data from the chloroplast psbA-trnH spacer and the nuclear ribosomal DNA ITS region, and examined amplified fragment length polymorphisms (AFLPs). Both tetraploid species showed combinations of the molecular features of E. montanum and E. revolutum, providing evidence for their derivation from these two taxa. The ITS sequences differed by 7.6% in the two parent taxa, and both E. elegans and E. quinaultense showed a much greater resemblance to E. revolutum than to E. montanum. In contrast, both allotetraploids resembled E. montanum at nine and E. revolutum at only three of the 12 AFLP loci differentiating the parent taxa. The allotetraploid species exhibited 0.7% divergence in their ITS sequences, and differed at two AFLP loci. The psbA-trnH spacer sequence of E. revolutum contained a 13-base insertion that was absent in E. montanum, and was also lacking in one of the tetraploid taxa, E. quinaultense. In E. elegans this insertion was present in one of the sampled populations but not the other, suggesting that this species originated from at least two hybridization events involving different maternal parents. For both alloploid species the molecular contributions from each parent depended strongly on the particular trait under consideration.

Key words: AFLPs, allopolyploidy, Erythronium, ITS, Liliaceae, psbA-trnH spacer