Erythronium populations from the southwestern Olympic Mountains of Washington, U.S.A. are tetraploid (2n = 48) and are morphologically intermediate between two widespread diploid species of this region, the subalpine E. montanum and the low-elevation E. revolutum. The Olympic Mountains populations lie between the geographic and elevational ranges of E. montanum and E. revolutum and exhibit a combination of the isozyme characteristics of these two species, possessing 11 alleles in common with E. montanum and four in common with E. revolutum. The evidence supports their derivation from the above two species through allopolyploid hybridization, and they are described here as the new species Erythronium quinaultense.

Communicating Editor: Aaron Liston