''Calliergon cordifolium'' is a species of

moss Mosses are small, non-vascular flowerless plants in the taxonomic division Bryophyta (, ) '' sensu stricto''. Bryophyta (''sensu lato'', Schimp. 1879) may also refer to the parent group bryophytes, which comprise liverworts, mosses, and hor ...

in the Calliergonaceae family, commonly known as the calliergon moss (though this name refers to the genus ''

Calliergon ''Calliergon'' is a genus of moss in the order Hypnales. The species in the genus are commonly referred to as calliergon mosses. Species The following species are recognised in the genus ''Calliergon'': *'' Calliergon cordifolium'' (Hedw.) Kind ...

'' generally) or heart-leaved spearmoss. The species is abundant in the right habitat, and grows in marshes and wet woodland, especially woodland of

alder Alders are trees comprising the genus ''Alnus'' in the birch family Betulaceae. The genus comprises about 35 species of monoecious trees and shrubs, a few reaching a large size, distributed throughout the north temperate zone with a few sp ...

(''Alnus'') or

willow Willows, also called sallows and osiers, from the genus ''Salix'', comprise around 400 speciesMabberley, D.J. 1997. The Plant Book, Cambridge University Press #2: Cambridge. of typically deciduous trees and shrubs, found primarily on moist s ...

(''Salix''), as well as around streams, ditches and pools. The species grows in tufts among other moss species. ''Calliergon cordifolium'' requires a wet environment to grow, and often grows completely submerged in water. It typically prefers lowland, but has been recorded as high as above sea level in

Inverness Inverness (; from the gd, Inbhir Nis , meaning "Mouth of the River Ness"; sco, Innerness) is a city in the Scottish Highlands. It is the administrative centre for The Highland Council and is regarded as the capital of the Highlands. Histori ...

, Scotland. The species has a circumpolar Boreo-temperate distribution. It is found throughout Europe (including north, into the

Arctic Circle The Arctic Circle is one of the two polar circles, and the most northerly of the five major circles of latitude as shown on maps of Earth. Its southern equivalent is the Antarctic Circle. The Arctic Circle marks the southernmost latitude at w ...

Svalbard Svalbard ( , ), also known as Spitsbergen, or Spitzbergen, is a Norwegian archipelago in the Arctic Ocean. North of mainland Europe, it is about midway between the northern coast of Norway and the North Pole. The islands of the group range ...

, the

Faeroe Islands The Faroe Islands ( ), or simply the Faroes ( fo, Føroyar ; da, Færøerne ), are a North Atlantic island group and an autonomous territory of the Kingdom of Denmark. They are located north-northwest of Scotland, and about halfway betwee ...

, Iceland and Greenland - and east into the

Caucasus The Caucasus () or Caucasia (), is a region between the Black Sea and the Caspian Sea, mainly comprising Armenia, Azerbaijan, Georgia, and parts of Southern Russia. The Caucasus Mountains, including the Greater Caucasus range, have historically ...

). It has been recorded in north and central Asia, as well as Turkey and Japan, throughout North America and in New Zealand. ''Calliergon cordifolium'' is a medium-sized to large moss with erect, green shoots. The shoots can reach up to , with egg-shaped leaves from wide. The leaves extend outwards, away from the stem. Towards the base, the leaves take on a heart shape, while, at the tip, they are rounded. The

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

-bearing capsules are rarely seen, and are encountered only in spring or summer. The spores measure 10 to 16

micrometre The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...

s across. ''Calliergon cordifolium'' can be mistaken for similar species, including ''

Calliergon giganteum ''Calliergon giganteum'', the giant spearmoss, giant calliergon moss, or arctic moss, is an aquatic plant found on lake beds in tundra regions. It has no wood stems or flowers, and has small rootlets instead of roots. ''Calliergon giganteum'' su ...

'', '' Calliergonella cuspidata'', ''

Straminergon stramineum ''Straminergon'' is a genus of mosses belonging to the family Amblystegiaceae. The genus has almost cosmopolitan distribution In biogeography, cosmopolitan distribution is the term for the range of a taxon that extends across all or most of ...

'' and '' Pseudocalliergon trifarium''.

References

{{Taxonbar, from=Q5022106 Hypnales Flora of Bulgaria Flora of Europe Flora of temperate Asia Flora of North America Flora of New Zealand