Non-vascular plants, also called bryophytes, are plants which do not possess a vascular system to transport water and nutrients. This group includes mosses, hornworts, and liverworts. Moss grows in thick carpets while hornworts and liverworts usually grow in ribbons or other unusual shapes. They are simple in morphology and structure, as they do not have roots or any woody parts, and do not produce flowers or seeds. Instead, they reproduce with spores. Bryophytes include some of the oldest-known plants, but today their diversity is low compared to vascular plants: there are about 260,000 species of known vascular plants, but only up to 23,000 known species of bryophytes. However, bryophytes species can adapt to harsher conditions than land plants, and seem to thrive in places where the conditions would be difficult for vascular plants. As a result, their biodiversity increases in the Arctic compared to vascular plants, with a ratio of only 2.5 times more vascular plants species than bryophyte species. Bryophytes can be a very important group in tundra habitats, especially mosses.
Hornworts have the lowest diversity of bryophytes, with about 200-250 known species. These species are mostly tropical and subtropical organisms which are not present above the Arctic circle. One species has been found in Iceland, the Carolina hornwort Phaeoceros carolinianus, which only grows in geothermal zones.
Liverworts are considered to be the oldest known living plants. Most species grow in flat leafy shapes, while others grow as flat ribbons. Unlike hornworts, they are cosmopolitan, and although their diversity is high around the tropics, it is also high in northern Europe in Iceland. For example, around 140 species of liverworts are found in Iceland and 173 in Greenland, out of 7,000-9,000 species worldwide. Some examples of East Atlantic Arctic liverworts include:
- Hill notchwort Barbilophozia sudetica. This species is common in Icelandic lava field habitats, and it is also found in Fennoscandia, Svalbard and the Faroe Islands, where it is rare. The genus Lophozia is one of the most diverse in the East Atlantic Arctic. Some species in this genus, such as Lophozia badensis or Lophozia hyperarctica, are found both in Svalbard and Greenland.
- Round-fruited flapwort Solenostoma confertissimum. This species has a circumpolar distribution. In the East Atlantic Arctic, it is found in Fennoscandia, Iceland, the Faroe Islands, Svalbard, and Greenland.
- Comb notchwort Anastrophyllum minutum. This species is found in Europe and North America, including Iceland, Fennoscandia, Greenland, and Svalbard. However, it has not been found in the Faroe Islands.
Mosses are a group of simple non-vascular plants which usually grow low to the ground in mats or clumps. They have the highest diversity of species among bryophytes, overall as well as in the Arctic and subarctic. Mosses can be defining plants in some Arctic habitats, such as tundra or Icelandic lava fields. They are resilient organisms that have important ecological and stabilizing roles in Arctic ecosystems.
Lava field covered with woolly fringe-moss.
Some examples of Arctic moss families include:
- Forkmosses (Dicranum species). Some species of forkmosses can be important for subarctic ecosystems. For example, Dicranum polysetum can be one of the first plants to regrow after a boreal forest fire.
- Peatmosses (Sphagnum species). These species have an important biological role in low Arctic and subarctic peat bogs, where they help in the fixation of nitrogen, an important nutrient for the growth of other plants.
- Woolly fringe-mosses (Racomitrium species). Some species of these mosses are some of the most common plants in Iceland.
- "Dicranum" by Andres Papp is licensed under CC BY 2.0.
- "Hornwort (Phaeoceros carolinianus)" by Poytr is licensed under CC BY-NC 2.0.
- "File:Phaeoceros carolinianus (a, 122441-471446) 1069.JPG" by HermannSchachner is marked with CC0 1.0
- "File:Lophozia sudetica (a, 142607-472624) 0550.JPG" by HermannSchachner is marked with CC0 1.0.
- "File:Jungermannia confertissima (a, 133750-471732) 1236.JPG" by HermannSchachner is licensed under CC0 1.0.
- "File:Anastrophyllum minutum (a, 142634-474025) 4367.JPG" by HermannSchachner is licensed under CC0 1.0.
- "Dicranum majus 2" by Scott Zona is licensed under CC BY-NC 2.0.
- "Sphagnum Moss" by Andrea Pokrzywinski is licensed under CC BY 2.0.
- "Racomitrium lanuginosum (hoary rock-moss)" by Tab Tannery is licensed under CC BY-NC-SA 2.0.
- Damsholt, K. (2017). The complex liverwort flora of the Faeroe Isles. Https://Doi.Org/10.25227/Linbg.01090, 40(5), 14–38. https://doi.org/10.25227/LINBG.01090
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- Icelandic Institute of Natural History. http://www.ni.is/biota/plantae.
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- Turetsky, M. R., Bond-Lamberty, B., Euskirchen, E., Talbot, J., Frolking, S., McGuire, A. D., & Tuittila, E. S. (2012). The resilience and functional role of moss in boreal and arctic ecosystems. New Phytologist, 196(1), 49–67. https://doi.org/10.1111/J.1469-8137.2012.04254.X