Schistidium tenerum

Common Name: Slender Schistidium
Scientific Name: Schistidium tenerum (Zett.) Nyh.
Recent synonyms: Grimmia tenera Zett.
Division: Bryophyta
Class: Bryopsida
Order: Grimmiales
Family: Grimmiaceae
Taxonomic Note: None
Technical Description: Plants dark green to brownish-green, hoary
above, in dense, compact, fragile tufts or cushions up to 2(4) cm tall;
leaves lanceolate to ovate-lancoeolate, 0.6–2.4 × 0.2–0.55 mm, concave,
margins recurved, entire; apex acute, upper leaves ending in a short or
long (1 mm) spinulose-denticulate hairpoint; costa ending just below the
apex; upper medial cells quadrate to irregularly rounded to shortrectangular; 5–11 µm, lamina, unistratose below, often bistratose
patches above; basal cells often elongated ± indistinctly sinuose.
Dioicous; seta very short, 0.4–0.6 mm, capsule deeply immersed, dark
reddish to orange-brown, ovoid, wide-mouth; peristome orange to light
brown, papillose, strongly perforated; spores 10–14 µm, smooth to
Distinctive characters: (1) recurved margins (2) bistratose patches in
the upper leaf lamina (3) loose, fragile tufts or cushions.
Similar species: Schistidium heterophyllum is distinguished from S.
tenerum by having an even 2-stratose upper lamina and plane to
incurved leaf margins.
Other descriptions and illustrations: Ireland 1964; Lawton 1971;
Nyholm 1956; McIntosh 2007.
Life History: Specific details for this species are not well documented.
In general the protonema, spore germination and development are typical
of all mosses. According to Blom ( 1995), Bremer (1980), and Nyholm
(1956) sporophytes are very rare. Schofield (1976) comments that in
British Columbia sporophytes are unknown. When capsules are present
according to McIntosh (2007) they mature in late spring to early summer.
Range, Distribution, and Abundance: Schistidium tenerum is known
from Eurasia, Greenland and North America. In the Pacific Northwestern
North America it occurs in Alaska, British Columbia, Alberta,
Washington, Oregon, Montana, Colorado and Wyoming According to
Norris & Shevock (2004) it has also been found in California.
Oregon Natural Heritage Information Center reports it from Josephine
County in the Klamath Mountain Ecoregion.
BLM: Documented on Medford District
USFS: Documented on the Mt. Baker-Snoqualmie and Okanogan
National Forests
Other: Documented on Olympic National Park
Habitat Associations: Schistidium tenerum occurs on exposed, dry rock
outcrops and on moist shaded soil in crevices on a rock outcrop.
According to Spence (1986) in British Columbia and Washington, S.
tenerum is a montane-restricted species. Collections from Washington
ranged from 5700 to 6736 feet elevation.
Threats: Ski lift, trail or road construction could pose a threat to this
species. Rock climbing in areas with known populations could also be a
threat to the species.
Conservation Considerations: All known localities could be revisited to
determine the extent of the populations and characterize habitats. It
would be good to explore similar habitat to find new populations.
Because this species appears to be restricted in Western North America
to high elevations it is suggested that the collection from Josephine
County be verified by an expert on Schistidium.
Conservation Rankings and Status:
Global: G5?, Oregon (S1), Colorado (S1/S3)
Oregon: ORNHIC List 3
Washington: Not ranked
BLM Strategic Species in Oregon
Preparer: Judith A. Harpel Ph.D.
Date Completed: November 2008
Revised by Candace Fallon, February 2011
(Revision only adds Attachment 1, Photos)
Blom, H. H. 1995. A revision of the Schistidium apocarpum complex in
Norway and Sweden. Bryophytorum Bibliotheca Band XX. J.
Cramer. Berlin. Germany. 320 pp.
Bremer, B. 1980. A taxonomic revision of Schistidium (Grimmiaceae,
Bryophyta) 2. Lindbergia 6: 89-117.
Ireland, R. R. 1964. Grimmia tenera Zett. and its Occurrence in North
America. The Bryologist. 67(2): 174-175.
Lawton. E. 1971. Moss Flora of the Pacific Northwest. The Hattori
Botanical Laboratory. Nichinan, Miyazaki, Japan. 362 pp.
McIntosh, T. 2007. Schistidium in Flora of North America North of
Mexico. Bryophyta Vol. 27 Part 1: 207-225. Oxford Univ. Press.
NatureServe Explorer. 2008. An Online Encyclopedia of Life.
Norris, D. & J. Shevock. 2004. Contributions Toward A Bryoflora of
California: I A Specimen-Based Catalogue of Mosses. Madrono
51(1): 1-131.
Nyholm, E. 1956. Illustrated Moss Flora of Fennoscandia. II. Musci.
Fasc. 2. GWK Gleerup, Lund, Sweden. 142-146 pp .
Schofield, W.B. 1976. Bryophytes of British Columbia III: habitat and
distributional information for selected mosses. Syesis 9: 317 –
Spence, J. 1986. Bryogeography of the Montane Moss Flora of
Southwestern British Columbia and Northwestern Washington
State. unpublished Ph.D. Thesis. University of British Columbia.
Vancouver, BC. 633 pp.
Attachment 1 – Photos
All photos by J. Harpel, under contract with the Oregon/Washington Bureau of Land
Alar and basal cells
Upper medial cells
Leaf cross section
Leaf apex
Wet individual
Whole mount dry
Whole mount wet
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