R. roseum
A
widespread boreal and hemiboreal species, absent from areas with
high calcium content where it is replaced by R. ontariense. Leaf
rosette features are helpful in recognizing this species.
— Plants
with 25–35[–45] rosette-forming leaves; leaves 2.5–3.5 mm
wide; leaf margins revolute up to 360°; costa in cross section with
large stereid band and unistratose, dorsal epidermis 2. R. ontariense
A
widespread species in Asian Russia, common in the Caucasus and with
a scattered distribution in calcareous areas of European Russia. The
rosette leaves in R. ontariense are more
numerous than those in R. roseum, and this
makes its habit quite distinct from that species. Also, the leaves
of R. roseum
are dark-green, while those of R. ontariense are
yellow-green.