Belongs within: Hypnales.
Hypnum is a large genus of mosses found worldwide. While more clearly defined than in the past, Hypnum remains a repository for a number of pleurocarpous mosses of less certain relationships, and its content may still require revision. Species within the genus are predominantly distinguished by features of the gametophytes, but this may be complicated by a certain degree of morphological plasticity in relation to growth habitat. Members of the subgenus Limnobium, characterised by soft, flaccid leaves, are semi-aquatic and generally found on wet rocks (Dixon 1924).
Characters (from Smith 2004): Autoicous or dioicous. Stems creeping to erect, more or less unbranched to closely pinnately branched. Branches long or short. Pseudoparaphyllia usually present. Stem leaves straight to falcate or circinate, secund, narrowly lanceolate to broadly ovate, gradually or abruptly narrowed to acute to filiform apex; margins plane or recurved, entire or denticulate; costa short and double or absent; basal cells usually narrowly rhomboidal, incrassate, porose or not, alar cells distinct, quadrate to rectangular, thin-walled to incrassate, hyaline or not, cells above elliptical to linear-vermicular. Branch leaves more or less similar to stem leaves but smaller. Setae long, reddish, smooth; capsules erect to horizontal, obloid to cylindrical, straight or curved; lid mamillate to conical with subulate beak; exostome teeth transversely striate below, longitudinally point-striate, papillose or smooth above, endostome with tall basal membrane and cilia.
<==Hypnum Hedw. 1801 (nom. cons.)SK02 [incl. Breidleria Loeske 1910OZB-O03] |--H. subg. DrepaniumD24 | | i. s.: H. circinaleD24 | |--H. sect. HypnumS04 | | |--H. andoi Sm. 1981 [incl. H. cupressiforme var. mammillatum]S04 | | |--H. cupressiforme Hedw. 1801D24, SK02 (see below for synonymy) | | | |--H. c. var. cupressiforme [incl. H. c. var. minus, Stereodon cupressiformis var. minor]SK02 | | | |--H. c. var. mossmanianum (Müll.Hal.) Ando 1982 (see below for synonymy)SK02 | | | `--H. c. var. subjulaceum Molendo 1865OZB-O03 | | |--H. imponens Hedw. 1801S04 (see below for synonymy) | | |--H. jutlandicum Holmen & Warncke 1969 [incl. H. cupressiforme var. ericetorum]S04 | | |--H. lacunosum (Brid.) Hoffmann ex Brid. 1819S04 [=H. cupressiforme var. lacunosum Brid. 1801SK02] | | | |--H. l. var. lacunosumS04 [incl. H. arcuatum f. elatumOZB-O03, H. cupressiforme var. elatumS04] | | | `--H. l. var. tectorum (Brid.) Frahm 1976 [=H. cupressiforme var. tectorum]S04 | | |--H. resupinatum Taylor 1849S04 (see below for synonymy) | | `--H. uncinulatum Jur. 1886S04 [incl. H. canarienseS04, Stereodon canariensisD24] | |--H. sect. Banbergeri Ando 1973S04 | | `--H. bambergeri Schimp. 1860D24, S04 (see below for synonymy) | |--H. sect. Hamulosa Schimp. in Bruch, Schimp. & Gümbel 1854OZB-O03 | | |--H. callichroum Brid. 1827D24, S04 [=Drepanium callichroumOZB-O03, Stereodon callichrousD24; incl. H. rupestreD24] | | `--H. hamulosum Schimp. in Bruch, Schimp. & Gümbel 1854D24, S04 (see below for synonymy) | |--H. sect. Pratensia Schimp. in Bruch, Schimp. & Gümbel 1854OZB-O03 | | `--H. pratense Koch ex Spruce 1845OZB-O03, D24, OZB-O03 (see below for synonymy) | `--H. sect. Revolutohypnum Mönk. 1927S04 | |--H. pallescens (Hedw.) Beauv. 1805 (see below for synonymy)OZB-O03 | |--H. recurvatum (Lindb. & Arnell) Kindb. 1891 (see below for synonymy)OZB-O03 | |--H. revolutum (Mitt.) Lindb. 1867D24, S04 (see below for synonymy) | | |--H. r. var. revolutumS04 | | `--H. r. var. dolomiticum (Milde) Mönk. 1927S04 | |--H. sauteri Schimp. in Saut. 1850 [=Drepanium sauteri, Stereodon fastigiatus var. sauteri]OZB-O03 | `--H. vaucheri Lesq. 1846S04 (see below for synonymy) `--H. (subg. Harpidium) capillifoliumD24 Hypnum incertae sedis: H. alternans Brid. 1801SK02 H. campbellianum [=Thuidium campbellianum; incl. Aequatoriella bifaria]SK02 H. castrenseH04 H. chrysogaster Müll.Hal. 1851 (see below for synonymy)SK02 H. eretiusculum [=Breidleria eretiuscula]OZB-O03 H. fuegianumD03 H. nelsonii (Broth.) Paris 1896 [=Stereodon nelsonii]SK02 H. perplicatum Dusén 1903D03 H. polypterumJ87 H. subchrysogaster (Broth.) Paris 1900 [=Stereodon subchrysogaster]SK02 H. sect. Fertilia Ando 1973OZB-O03 `--H. fertile Sendtn. 1841 [=Drepanium fertile, Sanionia fertilis, Stereodon fertilis]OZB-O03 H. sect. Pseudostereodon (Broth.) Ando 1973OZB-O03 Nomina nuda: Hypnum antipodum Hampe 1880 [=Rhynchohypnum antipodum Hampe ex Wijk, Margad. & Florsch. 1967, Rhynchostegium antipodum Mitt. 1882]SK02 Hypnum austromontanum Hampe 1880 [=Rhynchostegium austromontanum Mitt. 1882]SK02 Hypnum brachytheciella Müll.Hal. ex Bailey 1886 [=Rhaphidostegium brachytheciella Müll.Hal. ex Burges 1935]SK02 Hypnum brevicolle Hampe 1880SK02 Hypnum decurvatum Hampe 1880 [=Porotrichum decurvatum Hampe ex Mitt. 1882]SK02 Hypnum exalare Müll.Hal. ex Bailey 1886SK02 Hypnum flagellaceum Paris 1900 [=Stereodon flagellaceus Broth. & Burchard ex Weymouth 1893]SK02 Hypnum hodgkinsoniae Müll.Hal. ex Muell. 1880SK02 Hypnum incurvum Hampe 1880 [=Rhynchostegium incurvum Mitt. 1882]SK02 Hypnum lineatum Hooker & Wilson ex Hampe 1880SK02 Hypnum luridulum Müll.Hal. ex Muell. 1880SK02 Hypnum microflagellare Müll.Hal. ex Bailey 1888SK02 Hypnum myurium Müll.Hal. ex Muell. 1880SK02 Hypnum novae-cambriae Hampe 1880 [=Porotrichum novae-cambriae Mitt. 1882]SK02 Hypnum obtusifolium Müll.Hal. ex Muell. 1880SK02 Hypnum parramattense Hampe & Müll.Hal. ex Hampe 1880 [=Rhynchostegium parramattense Mitt. 1882]SK02 Hypnum perpumilum Müll.Hal. ex Muell. 1880SK02 Hypnum pseudodemissum Müll.Hal. ex Hampe 1880SK02 Hypnum pseudohomomallum Müll.Hal. ex Geh. 1876SK02 Hypnum pseudopilaceum Hampe 1880 [=Porotrichum pseudopilaceum Mitt. 1882]SK02 Hypnum pseudopraelongum Müll.Hal. ex Muell. 1880SK02 Hypnum rubens Hampe & Müll.Hal. ex Paris 1898SK02 Hypnum strictiusculum Müll.Hal. ex Bailey 1886SK02 Hypnum strumiferum Hampe 1881 [=Rhynchostegium strumiferum Mitt. 1882]SK02 Hypnum subpungens Hampe & Müll.Hal. ex Hampe 1880SK02 Hypnum umbilicatulum Müll.Hal. ex Geh. 1876 [=Isopterygium umbilicatulum Mitt. 1882, Isothecium umbilicatulum Mitt. ex Wijk, Florsch. & Margad. 1964]SK02 Hypnum vesiculifolium Müll.Hal. ex Muell. 1880SK02 Hypnum wilhelmii Müll.Hal. ex Muell. 1880SK02
Hypnum bambergeri Schimp. 1860D24, S04 [=Drepanium bambergeriOZB-O03, Stereodon bambergeriD24; incl. H. bambergeri var. condensatumOZB-O03, H. condensatum var. flexuosumOZB-O03]
Hypnum chrysogaster Müll.Hal. 1851 [=H. cupressiforme var. chrysogaster, Stereodon chrysogaster; incl. H. patale]SK02
Hypnum cupressiforme Hedw. 1801D24, SK02 [=Drepanium cupressiformeOZB-O03, Stereodon cupressiformisSK02; incl. H. cupressiforme var. brevisetumOZB-O03, H. deflectensD24, Hypnum cupressiforme var. filiforme Brid. 1801S04, SK02, H. cupressiforme f. filiformisSK02, Stereodon cupressiforme var. filiformeM49, H. heseleriS04, H. teichophilumD24, H. cupressiforme var. uncinatulumOZB-O03]
Hypnum cupressiforme var. mossmanianum (Müll.Hal.) Ando 1982 [=Stereodon cupressiformis var. mossmanianus; incl. Drepanohypnum walterianum, Hypnum walterianum, H. walteri (l. c.), Isopterygium walterianum, Stereodon walterianus]SK02
Hypnum hamulosum Schimp. in Bruch, Schimp. & Gümbel 1854D24, S04 [=Drepanium hamulosumOZB-O03, H. cupressiforme var. hamulosumOZB-O03, Stereodon hamulosusD24]
Hypnum imponens Hedw. 1801S04 [=Drepanium imponensOZB-O03, H. cupressiforme ssp. imponensOZB-O03, Stereodon imponensD24]
Hypnum pallescens (Hedw.) Beauv. 1805 [=Drepanium pallescens, Homomallium pallescens, Leskea pallescens, Stereodon pallescens; incl. Hypnum pallescens var. perichaetiale, Drepanium reptile, Hypnum pallescens var. reptile, Stereodon reptilis, H. pallescens var. subjulaceum non H. cupressiforme var. subjulaceum Molendo 1865]OZB-O03
Hypnum pratense Koch ex Spruce 1845OZB-O03, D24, OZB-O03 [=Breidleria pratensisOZB-O03, Drepanium pratenseOZB-O03, Isopterygium pratenseD24]
Hypnum recurvatum (Lindb. & Arnell) Kindb. 1891 [incl. Drepanium fastigiatum, H. fastigiatum, Stereodon fastigiatus]OZB-O03
Hypnum resupinatum Taylor 1849S04 [=H. cupressiforme var. resupinatum (Taylor) Schimp. 1856OZB-O03, Stereodon resupinatusD24; incl. H. cupressiforme var. longirostreD24]
Hypnum revolutum (Mitt.) Lindb. 1867D24, S04 [=Stereodon revolutus Mitten 1859D24; incl. H. heufleriD24, H. plicatileD24, Stereodon plicatilisD24]
Hypnum vaucheri Lesq. 1846S04 [=Drepanium vaucheriOZB-O03, H. cupressiforme ssp. vaucheriOZB-O03, Stereodon vaucheriOZB-O03]
*Type species of generic name indicated
References
[D24] Dixon, H. N. 1924. The Student’s Handbook of British Mosses 3rd ed. V. V. Sumfield: Eastbourne.
[D03] Dusén, P. 1903. Patagonian and Fuegian mosses. In: Scott, W. B. (ed.) Reports of the Princeton University Expeditions to Patagonia, 1896–1899 vol. 8. Botany pp. 63–126. The University: Princeton (New Jersey).
[H04] Haeckel, E. 1899–1904. Kunstformen der Natur. Bibliographisches Institut: Leipzig und Wien.
[J87] Judd, W. S. 1987. Floristic study of Morne La Visite and Pic Macaya National Parks, Haiti. Bulletin of the Florida State Museum—Biological Sciences 32 (1): 1–136.
[M49] Martin, W. 1949. The bryophytes of Stewart Island.—Part I. Transactions and Proceedings of the Royal Society of New Zealand 77 (2): 257–277.
[OZB-O03] Ochyra, R., J. Żarnowiec & H. Bednarek-Ochyra. 2003. Census Catalogue of Polish Mosses. Institute of Botany, Polish Academy of Sciences: Cracow.
[S04] Smith, A. J. E. 2004. The Moss Flora of Britain and Ireland 2nd ed. Cambridge University Press.
[SK02] Streimann, H., & N. Klazenga. 2002. Catalogue of Australian Mosses. Flora of Australia Supplementary Series 17. Australian Biological Resources Study: Canberra.