Boechera holboellii or Holbøll's Rockcress is found in Greenland. Its cytology has been much studied by the Danish botanist Tyge W. Böcher. Circumscription of this species has varied, with earlier works treating it as a widespread, polymorphic species with several varieties, while more recently it has been treated as a much more narrowly defined species from Greenland. The rust fungus Puccinia monoica infects the plant leading to pseudoflowers, which mimic those of yellow, early spring wildflowers (e.g. buttercups), not only in visible light but also in ultraviolet.