''Ptychostomum knowltonii'' is a species of

moss Mosses are small, non-vascular plant, non-vascular flowerless plants in the taxonomic phylum, division Bryophyta (, ) ''sensu stricto''. Bryophyta (''sensu lato'', Wilhelm Philippe Schimper, Schimp. 1879) may also refer to the parent group bryo ...

belonging to the family

Bryaceae Bryaceae is a family of mosses.Buck, William R. & Bernard Goffinet. 2000. "Morphology and classification of mosses", pages 71-123 ''in'' A. Jonathan Shaw & Bernard Goffinet (Eds.), ''Bryophyte Biology''. (Cambridge: Cambridge University Press). . ...

. Its green leaves are ovate and strongly concave. It is native to

Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the equator. For other planets in the Solar System, north is defined by humans as being in the same celestial sphere, celestial hemisphere relative to the invariable plane of the Solar ...

References

Bryaceae Plants described in 2005 Flora of Northern America Flora of Europe {{Moss-stub