A new saxicolous Orthotrichum
species, O. dagestanicum sp. nov. is
described from the southern part of Dagestan
Republic (Eastern
Caucasus). The combination of hyaline and serrulate
leaf apices composed of elongate thick-walled cells, strongly 8-ribbed capsules, immersed stomata that are not strongly covered by
subsidiary cells, and paired exostome teeth indicate
its affinity to O. vittii F.Lara
et al., endemic of Iberian Peninsula, and O. garretii
Grout & Flowers from U.S.A.,
Utah. However,
8 non-appendiculate endostome
segments differ it from both species.