Arched Fern Moss - Thuidium recognitum
MNPS Threat Rank
Plants: Pleurocarpous (Vitt 1988). Growing in mats, pale green to green or brown with yellow tones. Stems creeping or bowed and sloping upwards (Crum & Anderson et al. 1981), bipinnate, fern-like (fanned and flattened), 4-9 cm in length (FNA 2014); paraphyllia numerous with branches thread-like or sometimes lance-shaped (Crum & Anderson et al. 1981).
Stem Leaves: Overlapping and appressed (Lawton 1981) or curving up and inward proximally with the tips spreading broadly when dry, spreading and with apices abruptly bent back and downward when wet, 1 mm in length, widely egg-shaped (FNA 2014) to lance-shaped with ovate tendencies (Lawton 1971), suddenly narrowing to an acumen, conspicuously folded longitudinally; margins mostly flat, seldom tightly rolled back and down below, finely saw-toothed from sharp papillae, especially apically; costa nearly the width of the acumen and vanishing close to the leaf tip (FNA 2014).
Branch Leaves: Primary branch leaves not as large as the stem leaves; costae shorter, not covered with papillae. Secondary leaves are smaller yet, ca 0.2 mm in length, their costae ending a little past mid-leaf or as short as 1/3 of the leaf length (FNA 2014).
Leaf Cells: Paraphyllia bearing papillae, chiefly at the upper ends of the cell, the end cell of each fork often sporting 2-3 papillae pointing in different directions (Crum & Anderson et al. 1981). Stem leaf laminal cells with 1 papilla on the dorsal-facing surface (FNA 2014), or basal and apical cells frequently smooth (Lawton 1971); upper laminal cells of the stem leaves diamond-shaped and sometimes somewhat elongated and rounded (FNA 2014), thick-walled (Crum & Anderson et al. 1981). Branch leaves bearing a papillose cell at the leaf tip, the cell with a somewhat squared end; branch leaf upper laminal cells diamond-shaped, incrassate, with 1 papilla on the dorsal-facing surface (Crum & Anderson et al. 1981), the apical cells frequently with 2 or more papillae (Lawton 1971).
Fruit ripens autumn through winter (FNA 2014).
North American Range
AK, BC to QC (except SK), WA and OR, WY, across much of the eastern United States, s to GA and extending w to MN, IA, KS, and OK (FNA 2014). Known in Montana from Cascade, Fergus, Flathead, Lake, and Meagher Counties (Elliott 2016).
Observations in Montana Natural Heritage Program Database
Number of Observations:
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Map Help and Descriptions
(Observations spanning multiple months or years are excluded from time charts)
On humus, damp soil and rock, less often on dead wood or bark, usually calcareous and wooded sites (Crum & Anderson et al. 1981); elevations ranging widely (FNA 2014).
Dioicous. Perichaetial leaves enlarged, to 4.2 mm in length, with finely toothed edges. Seta somewhat red, 20-42 mm tall. Capsule 2-3.5 mm in length, level, bowed (Crum & Anderson et al. 1981); endostome sections without openings; cilia of the endostome joined in 2s and 3s (FNA 2014).
- Literature Cited AboveLegend: View Online Publication
- Crum, H.A. and L.E. Anderson. 1981. Mosses of Eastern North America. 2 volumes. Columbia University Press, New York. 1328 pp.
- 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
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- 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.
- Smith, A.J.E. 1980. The Moss Flora of Britain and Ireland. Cambridge University Press, Cambridge. 705 pp.