Publication: Nordic J. Bot. 26: 47. 2008.
selected vouchers: WTU
Notes: Known only from a single collection (1963) in Skagit County, with no additional reports since.
FNA8: "Kalmia procumbens is the only species of the genus that is not endemic to North America. An attractive dwarf shrub, it is sometimes cultivated in rock gardens.
The inclusion here of Kalmia procumbens and K. buxifolia, traditionally treated as the monotypic genera Loiseleuria and Leiophyllum, is in keeping with the results of recent morphological and molecular phylogenetic studies. P. F. Stevens et al. (2004) also included Leiophyllum and Loiseleuria within an expanded Kalmia. These two species have evolved deeply cleft corollas with nearly separate petals, and thus lost the characteristic pockets of Kalmia; otherwise they are typical for the genus."