Skip to main content Skip to main navigation menu Skip to site footer
Type: Article
Published: 2021-06-30
Page range: 98–111
Abstract views: 928
PDF downloaded: 909

The diversity of the Polytrichopsida—a review

Royal Botanic Garden Edinburgh, 20A Inverleith Row, Edinburgh, EH3 5LR, Scotland
Royal Botanic Garden Edinburgh, 20A Inverleith Row, Edinburgh, EH3 5LR, Scotland; Department of Botany, Faculty of Applied Sciences, University of Sri Jayewardenepura, Gangodawila, Nugegoda, Sri Lanka
Finnish Museum of Natural History (Botany), PO Box 7, 00014 Univ. Helsinki, Finland
Finnish Museum of Natural History (Botany), PO Box 7, 00014 Univ. Helsinki, Finland; Organismal & Evol. Biology & Viikki Plant Sci. Center, Univ. Helsinki, Finland
bryophytes cladistics fossils mosses nomenclature phylogeny systematics taxonomy


The class Polytrichopsida are a phylogenetically isolated moss lineage of around 200 species. The nematodontous peristome found in most species has a fundamentally different structure from the arthrodontous peristome of the Bryopsida and may be independently evolved from an ancestral type of spore dehiscence apparatus. Within the class generic circumscriptions and relationships are now fairly confidently resolved and more or less congruent with the most developed pre-molecular taxonomy. Drawing on previously published datasets, we conducted a phylogenetic analysis of a novel matrix of terminals representing diversity across the Polytrichopsida. The class comprises 17 extant genera and two known only from fossils. Most of these are numerically small, the most notable exception being Pogonatum with over 50 species. Considering current phylogenetic hypotheses in the light of morphology and global distributions, Alophosia, Bartramiopsis and Lyellia, the earliest diverging lineages according to recent phylogenetic analyses, appear to be relicts, with scattered and disjunct distributions. All of these genera lack peristomes, while all later originating lineages have nematodontous peristomes developed from bundles of “u-shaped” whole cells. The genus Dawsonia, sister to all other peristomate taxa, differs in its unique peristome composed of long, bristle-like teeth arranged in concentric layers. Many members of some traditional genera found to be polyphyletic in recent studies are part of a southern hemisphere grade and only distantly related to the superficially similar northern hemisphere species with which they were historically classified. A large apical clade including eight genera accounts for the majority of the diversity, these being most speciose in northern temperate regions or the Asian tropics. Many of the Polytrichopsida are relatively large plants with well-developed vasculature and a “pseudo-mesophyll” capable of supporting relatively high rates of photosynthesis in moist, well-illuminated environments. With ten described species, Cenozoic fossils of Polytrichopsida are fairly numerous compared with other mosses. Records of fossils from older sediments have been rare, but recently several well-preserved fossils of Polytrichopsida have been found, most of which still await detailed description.


Download data is not yet available.


  1. Akaike, H. (1974) A new look at the statistical model identification. IEEE Trans. Automatic Control 19: 716–723.

  2. Allen, B. (2018) Moss flora of Central America. Part 4. Fabroniaceae–Polytrichaceae. Missouri Botanical Garden Press, 840 pp.

  3. Aponte, R.A. & Uribe, M.J. (2017) Revisión de la familia Polytrichaceae (Bryophyta) para Colombia. Boletín de la Sociedad Argentina de Botánica 52: 209–250.

  4. Atala, C. & Alfaro, J.F. (2012) Vascular architecture of the dendroid antipodean moss Dendroligotrichum dendroides (Brid. ex Hedw.) Broth. (Polytrichaceae). Journal of Bryology 34: 277–280.

  5. Bell, N.E. & Hyvönen, J. (2008) Rooting the Polytrichopsida: the phylogenetic position of Atrichopsis and the independent origin of the polytrichopsid peristome. In: Mohamed, H. (Ed.) Bryology in the new millennium. University of Malaya, Kuala Lumpur, pp. 227–239.

  6. Bell, N.E. & Hyvönen, J. (2010a) Phylogeny of the moss class Polytrichopsida (Bryophyta): generic level structure and incongruent gene trees. Molecular Phylogenetics & Evolution 55: 381–398.

  7. Bell, N.E. & Hyvönen, J. (2010b) A phylogenetic circumscription of Polytrichastrum (Polytrichaceae): Reassessment of sporophyte morphology supports molecular phylogeny. American Journal of Botany 97: 566–578.

  8. Bell, N.E. & Hyvönen, J. (2012) Gametophytic simplicity in Laurasian and Gondwanan Polytrichopsida—The phylogeny and taxonomy of the Oligotrichum morphology. Journal of Bryology 34: 160–172.

  9. Bell, N.E., Kariyawasam, I.U., Hedderson, T.A.J. & Hyvönen, J. (2015) Delongia gen. nov., a new genus of Polytrichaceae (Bryophyta) with two disjunct species in East Africa and the Himalaya. Taxon 64: 893–910.

  10. Bell, N.E., Hyvönen, J., Yao, K.-Y. & Ma, W.-Z. (2017) Description and phylogenetic investigation of Pogonatum shevockii N.E.Bell & Hyvönen (Polytrichaceae), a new East Asian species with a unique leaf morphology. Journal of Bryology 39 (3): 235–246.

  11. Bell, N.E., Quandt, D., O’Brien, T.J. & Newton, A.E. (2007) Taxonomy and phylogeny in the earliest diverging pleurocarps: Square holes and bifurcating pegs. Bryologist 110: 533–560.[533:TAPITE]2.0.CO;2

  12. Biersma, E., Jackson, J., Hyvönen, J., Koskinen, S., Linse, K., Griffiths, H. & Convey, P. (2017) Global biogeographic patterns in bipolar moss species. Royal Society Open Science, 4 (7): 170147.

  13. Bippus, A.C., Stockey, R.A., Rothwell, G.W. & Tomescu, A.M.F. (2017) Extending the fossil record of Polytrichaceae: Early Cretaceous Meantoinea alophosioides gen. et sp. nov., permineralized gametophytes with gemma cups from Vancouver Island. American Journal of Botany 104: 584–597.

  14. Bippus, A., Escapa, I.E. & Tomescu, A.M.F. (2018) Wanted dead or alive (probably dead): stem group Polytrichaceae. American Journal Botany 105: 1–21.

  15. Bippus, A.C., Savoretti, A., Escapa, I.H., Garcia-Massini, H. & Guido, D. (2019) Heinrichsiella patagonica gen. et sp. nov.: A permineralized acrocarpous moss from the Jurassic of Patagonia. International Journal of Plant Sciences 180: 882–891.

  16. Brodribb, T., Carriquí, M., Delzon, S., McAdam, S. & Holbrook, N. (2020) Advanced vascular function discovered in a widespread moss. Nature Plants 6: 273–279.

  17. Brotherus, V.F. (1925) Musci (Laubmoose) 2. Hälfte. In: Engler, A. & Prantl, K. (Eds.) Die natürlichen Pflanzenfamilien. 2. Aufl. 11. Engelmann, Leipzig, 542 pp.

  18. Derda, G.S. & Wyatt, R. (2000) Isozyme evidence regarding the origins of three allopolyploid species of Polytrichastrum (Polytrichaceae, Bryophyta). Plant Systematics & Evolution 220: 37–53.

  19. De Sloover, J.L. (1986) Note de bryologie africaine XIII.—Polytrichaceae. Bulletin du Jardin botanique National de Belgique 56: 241–300.

  20. De Sousa, F., Foster, P.G., Donoghue, P.C.J., Schneider, H. & Cox, C.J. (2018) Nuclear protein phylogenies support the monophyly of the three bryophyte groups (Bryophyta Schimp.). New Phytologist 222: 565–575.

  21. Dodens, R. (1576) A Niewe Herball Translated by Henry Lyte. Gerard Dewes, London.

  22. Fleischer, M. (1923) Die Musci der Flora Buitenzorg (zugleich Laubmoosflora von Java). Flora de Buitenzorg V: 4.

  23. Flores, J.R., Bippus, A.C., Suárez, G.M. & Hyvönen, J. (2021) Defying death: incorporating fossils into the phylogeny of the complex thalloid liverworts (Marchantiidae, Marchantiophyta) confirms high order clades but reveals discrepancies in family‐level relationships. Cladistics [Online]

  24. Flores, J.R., Bippus, A.C., Tomescu, A., Bell, N. & Hyvönen, J. (2020) Rooting morphologically divergent taxa–slow-evolving sequence data might help. bioRxiv: 2020.03.15.983684.

  25. Forrest, L.L. (1995) A phylogenetic analysis of Polytrichaceae (Musci). M.Sc. thesis, Dept. Botany, Univ. Reading.

  26. Frahm, J.-P. (2004) The genus Atrichum in Baltic amber. Journal of the Hattori Botanical Laboratory 95: 219–227.

  27. Goebel, K. (1906) Archegoniatenstudien X. Flora 96: 1–202.

  28. Goryunov, D.V., Sotnikova, E.A., Goryunova, S.V., Kuznetsova,O.I., Logacheva, M.D., Milyutina, I.A., Fedorova, A.V., Fedosov, V.E. & Troitsky, A.V. (2021) The mitochondrial genome of nematodontous moss Polytrichum commune and analysis of intergenic repeats distribution among Bryophyta. Diversity 13 (2): 54.

  29. Hedwig, J. (1801) Species muscorum frondosorum. J. A. Barthii, Lipsiae Leipzig.

  30. Huttunen, S, Bell, N.E. & Hedenäs, L. (2018) The evolutionary diversity of mosses–taxonomic heterogeneity and its ecological drivers. Critical Reviews in Plant Sciences 37 (2–3): 128–174.

  31. Hyvönen, J. (1989) A synopsis of genus Pogonatum (Polytrichaceae, Musci). Acta Botanica Fennica 138: 1–87.

  32. Hyvönen, J. (2006) Genera Atrichum, Notoligotrichum, Pogonatum, Polytrichastrum, Polytrichum and Polytrichadelphus (Polytrichaceae). Flora of Australia 51: 124–127, 132–143.

  33. Hyvönen, J., Hedderson, T.A., Smith Merrill, G.L., Gibbings, J.G. & Koskinen, S. (1998) On phylogeny of the Polytrichales. Bryologist 101: 489–504.

  34. Hyvönen, J., Koskinen, S., Smith Merrill, G.L., Hedderson, T.A. & Stenroos, S. (2004) Phylogeny of the Polytrichales (Bryophyta) based on simultaneous analysis of molecular and morphological data. Molecular Phylogenetics & Evolution 31: 915–928.

  35. Ignatov, M.S. & Shcherbakov, D.E. (2009) A new fossil moss from the Lower Permian of the Russian Far East. Arctoa 18: 201–212 .

  36. Kariyawasam, I.U. & Long, D.G. & Bell, N.E. (2018) A taxonomic revision of Oligotrichum Lam. & DC. (Polytrichaceae) in the Sino-Himalaya. Journal of Bryology 40: 223–243.

  37. Kariyawasam, I., Price, M.J., Bell, N.E., Long, D.G., Mill, R.R. & Hyvönen, J. (2021) Unearthing a lectotype for Polytrichum commune Hedw. (Bryophyta, Polytrichaceae). Taxon. [Published Online]

  38. Konopka, A.S., Herendeen, P.S., Smith Merrill, G.L. & Crane, P.R. (1997) Sporophytes and gametophytes of Polytrichaceae from the Campanian (Late Cretaceous) of Georgia, USA. International Journal of Plant Sciences 158: 489–499.

  39. Koponen, T. & Piippo, S. (2002) Viktor Ferninand Brotherus and his collection of letters. Bryobrotherella 5: 1–29.

  40. Koskinen, S. & Hyvönen, J. (2004) Pogonatum (Polytrichales, Bryophyta) revisited. Molecular systematics of bryophytes. Monographs in systematic botany from the Missouri Botanical Garden 98: 255–69.

  41. Lehtonen, S., Poczai, P., Sablok, G., Hyvönen, J., Kargerr, D.N. & Flores, J. (2020) Exploring the phylogeny of the marattialean ferns. Cladistics 36: 569–593.

  42. Ligrone, R., Duckett, J.G. & Renzaglia, K.S. (2012) Major transitions in the evolution of early land plants: a bryological perspective. Annals of Botany 109: 851–871.

  43. Lindberg, S.O. (1868) Observationes de formis praesertim europaeis Polytrichoidearum (Bryacearum nematodontearum). Notiser ur Sällskapets pro Fauna et Flora Fennica förhandlingar 9: 91–158.

  44. Liu Y, Johnson, M.G., Cox, C.J., Medina, R., Devos, N., Vanderpoorten, A., Hedenäs, L., Bell, N.E., Shevock, J.R., Aguero, B., Quandt, D., Wickett, N.J., Shaw, A.J. & Goffinet, B. (2019) Resolution of the ordinal phylogeny of mosses using targeted exons from organellar and nuclear genomes. Nature Communications 10 (1): 1485.

  45. Long, D.G. (1985) Polytrichaceae. Illustrated moss flora of Arctic North America and Greenland. 1. Meddelelser om Greenland, Bioscience 17: 1–57.

  46. Marschall, M. & Proctor, M.C.F. (2004) Are bryophytes shade plants? Photosynthetic light responses, and proportions of chlorophyll a, chlorophyll b and total carotenoids. Annals of Botany 94: 593–603.

  47. Müller, J., Müller, K.F., Neihuis, C. & Quandt, D. (2011) PhyDE: Phylogenetic data editor, version 0.997. []

  48. Nyholm, E. (1971) Studies in the genus Atrichum P. Beauv. A short survey of the genus and the species. Lindbergia 1: 1–33.

  49. Nylander, J.A.A. (2004) MrModeltest, version 2.2. []

  50. Peralta, D.F. & Yano, O. (2010) Taxonomic treatment of the Polytrichaceae from Brazil. Bryologist 113: 646–672.

  51. Perley, D.S. & Jesson, L.K. (2015) Hybridization is associated with changes in sexual system in the bryophyte genus Atrichum. American Journal of Botany 102: 555–565.

  52. Proctor, M.C.F. (2005) Why do Polytrichaceae have lamellae? Journal of Bryology 27: 221–229.

  53. Quandt, D., Müller, K., Stech, M., Hilu, K.W., Frey, W., Frahm, J.-P. & Borsch, T. (2004) Molecular evolution of the chloroplast trnL-F region in land plants. Monographs in Systematic Botany from the Missouri Botanical Garden 98: 13–37.

  54. Quandt, D., Bell, N.E. & Stech, M. (2007) Unravelling the knot: The Pulchrinodaceae fam. nov. (Bryales). Beihefte Nova Hedwigia 131: 21–39.

  55. Quandt, D. & Stech, M. (2005) Molecular evolution of the trnL(UAA) intron in bryophytes. Molecular Phylogenetics & Evolution 36: 429–443.

  56. Renault, B. & Zeiller, R. (1888) Flore fossile de Commentry. Bulletin Soc. Industr. Min. 3e serie, tom. ii; Études sur le Terr. Houill. d. Commentry, Livre 2: 34.

  57. Renzaglia, K., Browning, W.B. & Merced, A. (2020) With over 60 independent losses, stomata are expendable in mosses. Frontiers in plant science 11: 567.

  58. Silvestro, D. & Michalak, I. (2012) raxmlGUI: A graphical front-end for RAxML. Organisms Diversity Evolution 12: 335–337.

  59. Smith, G.L. (1969) On Atrichopsis, with notes on some austral Psilopilum species. Bulletin of the Torrey Botanical Club 96: 60–69.

  60. Smith, G.L. (1971) A conspectus of the genera Polytrichaceae. Memoirs of the New York Botanical Garden 21: 1–83.

  61. Smith Merrill, G.L. (1993) Polytrichaceae. In: Sharp, A.J., Crum, H. & Eckel, P.M. (Eds.) Moss flora of Mexico, 69. Memoirs of the New York Botanical Garden, pp. i–xvii+1–1113.

  62. Smith Merrill, G.L. (1996) Hebantia, a new genus of Polytrichaceae (Bryophyta). Journal of the Hattori Botanical Laboratory 80: 247–250.

  63. Smith Merrill, G.L. (2007) Polytrichaceae. In: Flora of North America Editorial Committee (Org.) Flora of North America North of Mexico, Vol. 27. Bryophytes: Mosses, Part 1. Oxford University Press, New York, pp. 121–161.

  64. Stamatakis, A. (2006) RAxML-VI-HPC: Maximum likelihood-based phylogenetic analyses with thousands of taxa and mixed models. Bioinformatics 22: 2688–2690.

  65. Sutherland, J. (1689) Hortus Medicus Edinburgensis: or A Catalogue of the Plants in the Physical Garden at Edinburgh. Edinburgh: Heir of Andrew Anderson.

  66. Touw, A. (1986) A revision of Pogonatum sect. Racelopus, sect, nov., including Racelopus Dozy & Molk., Pseudoracelopus Broth, and Racelopodopsis Thér. Journal of the Hattori Botanical Laboratory 60: 1–33.

  67. Wang, Z., Bader, M.Y., Liu, X., Zhu, Z.M. & Bao, W.K. (2017) Comparisons of photosynthesis-related traits of 27 abundant or subordinate bryophyte species in a subalpine old-growth fir forest. Ecology & Evolution 7: 7454–7461.

  68. Zanten, B.O. van (1973) A taxonomic revision of the genus Dawsonia R. Brown. Lindbergia 2: 1–48.