Andreaea nivalis

Andreaea nivalis, commonly known as snow rock-moss,^[4] is a species of moss in the Andreaea family found in Alaska, California, Oregon, Washington, Greenland, Spain, Japan, Russia and Poland. It is black and reddish, dioicous, and grows on wet, acidic rocks. It is threatened by droughts and global warming, and is a near-threatened species on the IUCN red list.

Andreaea nivalis was first described in 1811.^[5] It is black and reddish, and grows in dense cushions.^[6] Its leaves can be secund to falcate-secund, meaning they can be sickle-shaped, and curved towards one side. They are mostly subulate, meaning they are awl-shaped.^[5] The leaves are mainly falcate-secund when dry. When moist, they are more spread out than when dry.^[7] The leaves have a strong costa, and they can have a width of 0.16 millimetres (0.0063 in) or more, and a length of 0.8 millimetres (0.031 in) or more. Andreaea nivalis has sharp laminal papillae on its dorsal side, which almost reach to its base, and a very short fruit stalk.^[6] Unlike other mosses in its species, which have six-valved capsules, Andreaea nivalis can have capsules with two or four valves. There is always one capsule on each fruiting plant.^[6]

Andreaea nivalis grows on wet acidic rocks, outcrops, and rocky areas,^[1] at medium to high elevations. It can be found in Greenland, Japan, Spain, Alaska, California, Oregon, and Washington.^[5] It has also been found in Poland and Spain.^[8][9] It is native to North America, Alaska, the UK, and Norway.^[10]

Andreaea nivalis es dioica , lo que significa que sus gametofitos solo producen espermatozoides u óvulos. ^{[ 5 ]} Sus hojas periqueciales , que encierran los arquegonios del musgo , llegan hasta la parte superior de las cápsulas del musgo. ^{[ 6 ]}

Andreaea nivalis está clasificada como casi amenazada en la lista roja de la UICN . Las principales amenazas para esta especie son la sequía y el calentamiento global . Su población está disminuyendo. La UICN ha recomendado la protección de tierras y aguas para conservar esta especie, e indica que se necesita investigación para monitorear las tendencias poblacionales de Andreaea nivalis . ^{[ 1 ]}

• Information about Andreaea nivalis at a USDA website