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BFNA | Family List | BFNA Vol. 2 | Hylocomiaceae

Rhytidiadelphus (Limpricht) Warnstorf, Krypt.-Fl. Brandenburg. 2: 842, 917. 1906.

Rhytidium, a moss genus, and Greek adelphus, brother, indicating a relationship between the two genera

J. R. Rohrer

  • Hylocomium subg. Rhytidiadelphus Limpricht

    Plants creeping to ascending or erect; growth monopodial. Stems irregularly and remotely branched to subpinnately branched, rarely with secondary branches; paraphyllia absent. Stem leaves erect-spreading to squarrose, squarrose-recurved, or falcate-secund, broadly ovate or ovate-triangular to ovate-lanceolate, sometimes plicate in proximal half of leaf, sometimes rugose, not or only slightly decurrent; margins serrulate distally, serrulate to nearly entire proximally; apex acuminate; costa double, short or extending to 2/3 leaf length; cells smooth or coarsely prorate; alar cells not differentiated or shorter and wider than basal cells. Branch leaves smaller, ovate to narrowly lanceolate, more abruptly acuminate. Capsule horizontal; operculum conic; exostome teeth cross-striolate to reticulate; endostome segments with broadly elliptic perforations along keel.

    Species 5 (5 in the flora): cool-temperate and boreal zones, North America, Eurasia, Atlantic Islands, Pacific Islands (New Zealand, Tasmania).


    Koponen, T. 1971. Rhytidiadelphus japonicus and R. subpinnatus. Hikobia 6: 18-35. Schofield, W. B. and S. S. Talbot. 1991. Rhytidiadelphus japonicus (Reimers) Kop. in North America. J. Hattori Bot. Lab. 69: 265-267.

    1 Leaves plicate; alar cells not or only slightly differentiated from the basal cells.   (2)
    + Leaves not plicate; alar cells differentiated from the basal cells.   (3)
    2 (1) Costa strong, extending at least to midleaf; leaf cells coarsely prorate; stem leaves gradually tapered to a broad, flat (occasionally rugose) acumen.   Rhytidiadelphus triquetrus
    + Costa weak, extending less than 1/4 leaf length; leaf cells smooth; abruptly narrowed to a slender, channeled, falcate-secund to recurved acumen.   Rhytidiadelphus loreus
    3 (1) Costa extending 1/3--1/2 leaf length; alar cells thick-walled and porose; stem leaves short acuminate.   Rhytidiadelphus japonicus
    + Costa extending to 1/3 leaf length; alar cells thin-walled and nonporose; stem leaves long-acuminate.   (4)
    4 (3) Stem leaves not crowded (stem visible between leaves) except at stem tip, erect-spreading to squarrose from nonsheathing broadly ovate-triangular base; plants irregularly branched to pinnately branched, inhabiting moist, usually shaded sites.   Rhytidiadelphus subpinnatus
    + Stem leaves crowded (stem concealed by leaves), strongly squarrose-recurved from subsheathing ovate base; plants remotely branched to irregularly pinnately branched, inhabiting well-drained, open to partially shaded sites, near the seacoast, or in grassy disturbed habitats.   Rhytidiadelphus squarrosus

    Lower Taxa

    Related Synonym(s):


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    Flora of North America  
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