Fragile Leaf Dicranum Moss - Dicranum fragilifolium
Plants: Acrocarpous (Vitt 1988), the tufts dense, shiny pale green to ochre. Stems heavily tomentose with deep brown or reddish rhizoids (FNA 2007).
Leaves: Upright-spreading, straight, firm, smooth, lying flat against the stem when dry, (5-)6-7(-7.5) mm long, 0.4-0.6 mm wide, concave below, becoming grooved above, the base lance-shaped, the fragile leaf tips deciduous and usually missing; costa 1/4-1/3 of leaf width at the base, extending beyond leaf tip to form a needle-like point, the outer surface smooth or a little rough, lacking ridges; margins smooth to finely toothed distally (FNA 2007).
Leaf Cells: Smooth, thick-walled (Lawton 1977), weakly bulging between laminal cells; alar region mostly 1-layered, occasionally 2-layered, well-defined, sometimes reaching the costa; costa with 1 line of guide cells; proximal laminal cells long and narrowly-rectangular, the walls usually pitted, sometimes faintly so (FNA 2007); median and distal laminal cells quadrate to short-rectangular and rounded, or erratically angled (Lawton 1971).
Capsules ripen in summer (FNA 2007).
Broken leaf tips lend a distinctive appearance to both Dicranum fragilifolium and D. tauricum, another species with fragile leaves, causing confusion where their ranges overlap. The capsules of D. fragilifolium are usually bowed; those of D. tauricum are straight. In sterile plants, check the X-section of the costa in the proximal half of the leaf. In D. fragilifolium, stereid cells occur in two narrow bands; there are none in D. tauricum (FNA 2007).
Greenland; Canada: AB, BC, MB, NL, NT, ON, QC, SK, YT; USA: AK, MI; Europe; Asia (FNA 2007). Known in Montana from Flathead County (Elliott 2016).
Observations in Montana Natural Heritage Program Database
Number of Observations:
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(Observations spanning multiple months or years are excluded from time charts)
Rotten wood and tree bases (Elliott 2016).
Dioicous; female plants wider than male plants, and similar in height. Seta ochre-brown, single, 15-25 mm. Capsule ochre, 1.8-2 mm, nearly upright, bowed or sometimes almost straight, rarely produced (FNA 2007).
It is thought that new plants are produced when the broken leaf tips are replaced (FNA 2007).
- 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. 2007. Flora of North America North of Mexico. Volume 27. Bryophytes: Mosses, Part 1. Oxford University Press, Inc., NY. xxi + 713 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.
- Malcolm, W. M., and Nancy Malcolm. 2000. Mosses and Other Bryophytes: An Illustrated Glossary. Nelson, New Zealand: Micro-Optics Press.