Picea × darwyniana Björk & Goward: an invalid taxonomic name

Abstract

Picea × darwyniana Björk & Goward was recently proposed to replace Picea albertiana S. Brown as the representative taxon for the hybrid offspring of Picea glauca (Moench) Voss and Picea engelmannii Parry ex Engelm., but should be considered invalid for three reasons. First, the proponents failed to document in any way that the P. albertiana S. Brown isotypes were Picea glauca × mariana Little & Pauley hybrids, as they claimed. Secondly, the P. albertiana S. Brown isotypes lacked pubescent twigs, purple markings on their seed-cones, and denticulate cone-scale margins, which are characteristics of P. glauca × mariana. This indicates a misinterpretation of the P. albertiana S. Brown parentage. Lastly, P. × darwyniana appears to be an example of P. albertiana ssp. ogilviei Strong & Hills. As the latter is an earlier and validly published name, P. × darwyniana is an illegitimate replacement for plants within the P. glauca × engelmannii (= P.a. ssp. albertiana) and P. engelmannii × glauca (= P.a. ssp. ogilviei) circumscriptions based on naming priority.