Question: Which genus is native to North America, Jovibarba or Dirca?
Sentence (from "Jovibarba"): "Jovibarba" have pale-greenish-yellow or yellow actinomorphic flowers with about six petals, while "Sempervivum" have generally pinkish flowers with around twice as many petals, which open more widely than jovibarba flowers.
Relevant evidence: No