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Knight's Plume Moss - Ptilium crista-castrensis
Other Names:  Ostrich-plume Feather Moss

Native Species

Global Rank: G5
State Rank: SNR

Agency Status
MNPS Threat Rank:

External Links

General Description
Plants: Pleurocarpous (Vitt 1988), growing in open mats, large, gleaming, deep green in shady habitats, ginger-gold to reddish-brown in open sites. The stems lack a hyalodermis, and possess paraphyllia and a feeble central strand. Stems nearly upright to ascending, pinnately branching, 3-10 cm in length, typically hooked at the ends. Branches at right angles to the stem, 3-15 mm in length, either narrowing or hooked at the ends (FNA 2014), the tips pointing toward the branch below (Lawton 1971), usually lacking rhizoids (FNA 2014).

Leaves: Stem and branch leaves differing. Stem leaves arising at right angles, widely ovate, broadest above the base, noticeably furrowed, 2-3 mm in length (FNA 2014), falcate-secund (Lawton 1971); margins plane, serrulate apically; apex acuminate; costa lacking or short and double. Branch leaves strongly curved and secund, directed toward the base of (rather than underside of) the main shoot, lanceolate, narrowing to the tip, furrowed, 1-2 mm in length; costa short and double (FNA 2014); apex more robustly serrate than on stem leaves (Lawton 1971).

Leaf Cells: Stem leaf Cells: Laminal cells smooth (FNA 2014), the walls thick (Lawton 1971), alar region distinct, the cells rectangular or square; distal cells typically longer than 6:1 (FNA 2014); basal cells wider and shorter than distal medial cells, porose (Lawton 1971). Branch leaf Cells: Long and narrow (FNA 2014).

Capsules ripen in fall (FNA 2014).

Diagnostic Characteristics
The leaves curve strongly, pointing toward the base of the main shoot. This distinguishes it from Hypnum species, in which the leaves are turned toward the underside of the shoot (FNA 2014).

The pinnate branching of Sanionia uncinata, a similar species, is not as even as that of Ptilium crista-castrensis (Vitt 1988).

Species Range

Range Comments
Greenland; Canada: AB, BC, MB, NB, NL, NS, NT, ON, PE, QC, SK, YT; USA: AK, CO, CT, IA, ID, MA, MD, ME, MI, MN, MT, NC, NE, NH, NJ, NY, PA, SD, TN, VT, VA, WA, WI, WV, WY; Europe; Asia (FNA 2014). In Montana, known from Carbon, Cascade, Flathead, Gallatin, Judith Basin, Lake, Lewis and Clark, Madison, Missoula, Park, Powell, Ravalli, and Sweet Grass Counties (Elliott 2016).

Observations in Montana Natural Heritage Program Database
Number of Observations: 14

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Humus and duff on coniferous forest floors (Elliott 2016; FNA 2014).

Reproductive Characteristics
Dioicous. Seta reddish-brown, 2-3 cm in length. Capsule cylindric, bowed, horizontal (FNA 2014) or slightly drooping, smooth, brown, the urn 2-3 mm in length; operculum up to 0.7 mm in length; apiculate (Lawton 1971); endostome segments with 2-3 cilia. Perichaetial leaves lance-shaped with an awl-shaped apex (FNA 2014).

  • Literature Cited AboveLegend:   View Online Publication
    • Elliott, J.C. and A.K. Pipp. 2018. A Checklist of Montana Mosses (1880-2018). Updated 3 January, 2020. Montana Natural Heritage Program, Helena, Montana. 73 pp.
    • Flora of North America Editorial Committee, eds. 2014. Flora of North America North of Mexico. Volume 28. Bryophytes: Mosses, Part 2. Oxford University Press, Inc., NY. xxi + 702 pp.
    • Lawton, E. 1971. Moss Flora of the Pacific Northwest. Hattori Botanical Laboratory. Japan: Yamabuki-cho, Shinjuku-ku, Tokyo. 362 pages plus appendices.
    • Vitt, D. J. Marsh, and R. Bovey. 1988. Mosses, Lichens & Ferns of Northwest North America. Seattle, WA: University of Washington Press. 296 p.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Lawton, E. 1971. Keys for the Identification of the Mosses on the Pacific Northwest. Reprinted from 'Moss Flora of the Pacific Northwest'. Published as Supplement No. 2 of the Journal of the Hattori Botanical Laboratory. Nichinan, Miyazaki, Japan. 66 pp.
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Citation for data on this website:
Knight's Plume Moss — Ptilium crista-castrensis.  Montana Field Guide.  .  Retrieved on , from