CITRINUM Zika, 2014
First published in Phytotaxa 159(2): 111-121, 2014.
Note : Sedum obtusatum ssp. boreale meanwhile has been published as a distinct species and named Sedum kiersteadiae.
See also A review of Sedum section Gormania (Crassulaceae) in western North America, in Phytotaxa 368 (1): 1-61, 2018.