Rhytidiadelphus squarrosus, photographed by James K. Lindsey.

Belongs within: Hypnales.

The Hylocomiaceae are a family of mosses found in cool temperate and arctic parts of the world. Hylocomium species are generally robust mosses, often with dense paraphyllia, and with rather large and short capsules (Dixon 1924).

Characters (from Smith 2004): Dioicous. Plants medium-sized to robust, forming mats to lax wefts. Stems procumbent to erect, irregularly to pinnately or subpinnately branched. Paraphyllia present or absent; pseudoparaphyllia usually present, foliose. Leaves erect to spreading or squarrose, plicate or not, broadly ovate to lanceolate, acuminate to rounded, base sometimes decurrent; margins often recurved below, usually denticulate to dentate; costa usually double, rarely single; alar cells differentiated or not, basal cells incrassate, porose, cells above narrowly elliptical to linear, sometimes prorate. Branch leaves narrower, smaller and often more sharply toothed than stem leaves. Setae smooth; capsules erect to pendulous; annulus of 1-3 rows of cells or absent; lid conical to longly rostrate; exostome teeth variously ornamented, endostome with high basal membrane, cilia 1-4, rarely absent; calyptrae cucullate.

<==Hylocomiaceae [Rhytidiaceae]
    |--Rhytidium (Sull.) Kindb. 1882OZB-O03, S04
    |    `--R. rugosum (Hedw.) Kindb. 1882S04 [=Hylocomium rugosumS04, Hypnum rugosumD24]
    |    |--Loeskeobryum Fleisch. in Broth. 1925OZB-O03, S04
    |    |    `--L. brevirostre (Brid.) Fleisch. in Broth. 1925S04 (see below for synonymy)
    |    |--Hylocomium Schimp. in Bruch, Schimp. & Gümbel 1852 (nom. cons.)S04
    |    |    |--H. himalayanumN02
    |    |    `--H. splendens (Hedw.) Schimp. in Bruch et al. 1852S04 (see below for synonymy)
    |    `--Hylocomiastrum Fleisch. in Broth. 1925OZB-O03, S04
    |         |--H. pyrenaicum (Spruce) Fleisch. in Broth. 1925S04 (see below for synonymy)
    |         `--H. umbratum (Hedw.) Fleisch. in Broth. 1925S04 [=Hylocomium umbratumS04, Hypnum proliferum var. umbratumOZB-O03]
         |--Pleurozium Mitt. 1869 (nom. cons.)OZB-O03, S04
         |    `--P. schreberi (Willd. ex Brid.) Mitt. 1869S04 (see below for synonymy)
         `--Rhytidiadelphus (Warnst.) Warnst. 1906OZB-O03, S04
              |--R. japonicusVHJ03
              |--R. loreus (Hedw.) Warnst. 1906S04 [=Hylocomium loreumS04, Hypnum loreumD24]
              |--R. squarrosus (Hedw.) Warnst. 1906SK02 [=Hylocomium squarrosumS04, Hypnum squarrosumD24]
              |--R. subpinnatus (Lindb.) Kop. 1971S04 (see below for synonymy)
              `--R. triquetrus (Hedw.) Warnst. 1906S04 (see below for synonymy)
Hylocomiaceae incertae sedis:
    |--L. hokinenseB-OO10
    `--L. tenueN02
    |--G. clarescensN02
    `--G. splendensF01
    |--M. javenseB-OO10
    |--M. macrocarpumN02
    |--M. stigmatophyllumN02
    `--M. submacrocarpumN02

Hylocomiastrum pyrenaicum (Spruce) Fleisch. in Broth. 1925S04 [=Hypnum pyrenaicum Spruce 1847D24, Hylocomium pyrenaicumS04, Pleurozium pyrenaicumOZB-O03, Ptychodium pyrenaicumOZB-O03; incl. Hylocomium oakesii Sullivant 1848D24, Hypnum oakesiiOZB-O03]

Hylocomium splendens (Hedw.) Schimp. in Bruch et al. 1852S04 [=Hypnum splendensD24; incl. Hyl. splendens f. alpinumOZB-O03, Hyl. splendens f. paludosumOZB-O03, Hyl. proliferumD24]

Loeskeobryum brevirostre (Brid.) Fleisch. in Broth. 1925S04 [=Hylocomium brevirostreS04, Hypnum brevirostreD24, Pleurozium brevirostrumOZB-O03, Rhytidiadelphus brevirostrisS04]

Pleurozium schreberi (Willd. ex Brid.) Mitt. 1869S04 [=Calliergonella schreberiOZB-O03, Entodon schreberiOZB-O03, Hypnopsis schreberiOZB-O03, Hypnum schreberiS04; incl. Hylocomium parietinumD24, Hypnum parietinumBS-V28, Entodon schreberi f. secundusOZB-O03]

Rhytidiadelphus subpinnatus (Lindb.) Kop. 1971S04 [=Hylocomium squarrosum var. subpinnatumD24, Hypnum subpinnatumOZB-O03; incl. Hylocomium squarrosum var. calvescensOZB-O03, Hypnum calvescensD24, Pleurozium calvescensOZB-O03, Rhytidiadelphus squarrosus ssp. calvescensS04]

Rhytidiadelphus triquetrus (Hedw.) Warnst. 1906S04 [=Hylocomium triquetrumS04, Hypnum triquetrumD24; incl. Hyl. corrugatulumD24]

*Type species of generic name indicated


[B-OO10] Bednarek-Ochyra, H., & R. Ochyra. 2010. Bucklandiella shevockii (Bryophyta, Grimmiaceae), an exquisite new species from Yunnan, China. Polish Botanical Journal 55 (2): 499–506.

[BS-V28] Bory de Saint-Vincent, J. B. 1828. Voyage Autour du Monde, Exécuté par Ordre du Roi, Sur la Corvette de Sa Majesté, La Coquille, pendant les années 1822, 1823, 1824 et 1825. Botanique. Cryptogamie. Arthus Bertrand: Paris.

[D24] Dixon, H. N. 1924. The Student’s Handbook of British Mosses 3rd ed. V. V. Sumfield: Eastbourne.

[F01] Furuki, T. 2001. Lethocolea naruto-toganensis, a new hepatic from swamps of Japan. Bryologist 104 (2): 306–309.

[N02] Negi, H. R. 2002. Abundance and diversity of moss communities of Chopta-Tunganath in the Garhwal Himalaya. Journal of the Bombay Natural History Society 99 (3): 418–433.

[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.

[VHJ03] Vanderpoorten, A., L. Hedenäs & A.-L. Jacquemart. 2003. Differentiation in DNA fingerprinting and morphology among species of the pleurocarpous moss genus, Rhytidiadelphus (Hylocomiaceae). Taxon 52: 229–236.

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