Hylocomiaceae

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 & 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
    |--Leptohymenium tenue N02
    |--Macrothamnium N02
    |    |--M. macrocarpum N02
    |    |--M. stigmatophyllum N02
    |    `--M. submacrocarpum N02
    |--Rhytidiadelphus (Limpr.) Warnst. 1906 VHJ03, SK02
    |    |--R. japonicus VHJ03
    |    |--R. loreus VHJ03
    |    |--R. squarrosus (Hedw.) Warnst. 1906 SK02
    |    |--R. subpinnatus VHJ03
    |    `--R. triquetrus VHJ03
    `--Hylocomium VHJ03
         |--H. brevirostre VHJ03 [=Hypnum brevirostre D24]
         |--H. loreum [=Hypnum loreum] D24
         |--H. himalayanum N02
         |--H. pyrenaicum [=Hypnum pyrenaicum Spruce 1847; incl. Hyl. oakesii Sullivant 1848] D24
         |--H. rugosum [=Hypnum rugosum] D24
         |--H. splendens [=Hypnum splendens; incl. Hyl. proliferum] D24
         |--H. squarrosum [=Hypnum squarrosum] D24
         |    |--H. s. var. squarrosum D24
         |    `--H. s. var. calvescens [=Hypnum calvescens; incl. Hyl. squarrosum var. subpinnatum] D24
         |--H. triquetrum [=Hypnum triquetrum; incl. Hyl. corrugatulum] D24
         `--H. umbratum [=Hypnum umbratum] D24

*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.

[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.

Smith, A. J. E., & R. Smith. 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.