''Andreaea nivalis'', also known as snow rock-moss, is a species of moss in the
Andreaea
''Andreaea'' is a genus of rock mosses described by Johann Hedwig in 1801.
They are small, delicate acrocarpous mosses (meaning that the capsules are formed at the tips of vertical branches) that form dark brown or reddish cushions on wet silic ...
family found in Alaska, California, Oregon, Washington, Greenland, Spain, Japan, Russia and Poland. It is black and reddish,
dioicous
Dioicy () is a sexual system where archegonia and antheridia are produced on separate gametophytes. It is one of the two main sexual systems in bryophytes. Both dioicous () and monoicous gametophytes produce gametes in gametangia by mitosis rathe ...
, and grows on wet, acidic rocks. It is threatened by
droughts
A drought is defined as drier than normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, an ...
and
global warming
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...
, and is a
near-threatened species
A near-threatened species is a species which has been categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature as that may be vulnerable to endangerment in the near future, but it does not currently qualify fo ...
on the
IUCN red list
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...
.
Description
''Andreaea nivalis'' was first described in 1811. It is black and reddish, and grows in dense cushions. Its leaves can be